L.S. Yevlashin, Yu.P. Maltsev (Polar Geophysical Institute, Apatity, Russia)
Two geomagnetic superstorms during the
maximum activity phase of solar cycle 22 on October 21-22, 1989 (min Dst
= -307 nT) and March 24-25, 1991 (min Dst = -298 nT) were chosen for the
analysis of geophysical situation. The first event is associated with the
flare X13.0/4B accompanied by the coronal mass ejection (CME). The second
one might have been produced by a CME driven interplanetary shock presumably
related to the X9.8/3B flare. Temporal behavior of Dst permitted to estimate
the IMF z component and dawn-to-dusk high-latitude difference.
Optical observations at the low latitude
stations Niigata and Moshiri (Japan) on October 21, 1989 showed that red
aurora appeared at the two intervals of 11.40-12.00 UT and 14.10-14.25
UT. Maximum 630.0 nm intensity was estimated to reach more the 80 kR, maximum
557.7 nm intensity was about 20 kR. Enhancements of low energy electrons
below 1 keV corresponding to the region of the auroral intensification
were found by DMSP satellite. On October 21, 1989 (15.0-18.00 UT) at Loparskaya
obs. (Kola peninsula) red type A auroras were observed with maximum 630.0
nm intensity of ~25 kR, maximum 557.7 nm intensity of ~10 kR.
During the storm main phase on March 24-25,
1991 at Loparskaya obs. instrumental and visual observations of auroras
were performed through the whole night. The intensity ratio I6300/I557.7
was more than 1 and red type A auroras were observed from 20.00 till 22.00
UT and also at 23.30 and 01.00 UT. It has been revealed that this auroral
emission characterised by extremely high intensity ratio of 630.0 nm to
557.7 nm was produced by the low energy electron precipitation.
SUBSTORM LARGE IMPULSIVE ELECTRIC FIELDS OBSERVED BY CRRES
T.V. Kozelova, B.V. Kozelov (Polar Geophysical
Institute, Apatity, Russia)
L.L. Lazutin (Skobeltsin Institute
of Nuclear Physics, Moscow State University, Moscow, Russia)
The CRRES satellite registered large (
20 mV/m) impulsive (~ 40 s) electric fields during substorms on L = 6 -
6.5. These E field impulses correlate with the rapid local reconfiguration
of the magnetic field and have inductive nature. Orientation of E field
in the impulses depends on the CRRES location. Near the inner edge of the
plasma sheet (event A), the E field had a dominant azimuthal (westward)
orientation. Near the outer boundary of the plasma sheet (event B), the
E field had a dominant Earthward direction. Besides, in both cases, some
initial perturbations of the E and B fields were present prior to the local
magnetic field reconfiguration. In the event A, the increase of the westward
E field and the enhancement of the current near the CRRES were observed.
This enhanced current may lead to a cross-field current instability and
further trigger local current disruption CD. In the event B, the initial
perturbation had the form of an oscillation of the Ey and Bz components
with a quasi-period of ~ 50 s. The electric field oscillation precedes
the magnetic oscillation by 90 degrees in phase, indicating at the even
mode standing wave structure. This oscillation may be a coupled shear Alfven
- slow magnetosonic mode associated with the ballooning - interchange instability.
Since analyzed electric and magnetic variations are associated with the
substorm expansion, we suppose that the rapid temporal development of the
initial perturbation arising from the cross-field current instability or
from the ballooning - interchange instability can lead to the nonlinear
process of local magnetic field reconfiguration, which will in turn induce
a large electric field.
RELATIONSHIP OF LONGITUDINAL LOCALIZATION OF SUBSTORM CENTER ON GEOSYNCHRONOUS ORBITS TO THE IMF By –COMPONENT
R.N. Boroyev, M.G. Gelberg (Institute of Cosmophysical Research and Aeronomy, Yakutsk, Russia)
In the paper the relationship of longitudinal
localization of substorm center on geosynchronous orbits to the IMF By
-component has been studied. It is shown that with the increase of the
By -component the local magnetic time of substorm center longitudinal
localization in the magnetosphere changed from the evening hours to the
morning ones. At low solar wind velocities the substorm center are localized
closer to the evening sector. The ionospheric projection of the magnetospheric
localization of the substorm center shifted in longitude westward at By
<0 and eastward at By >0. The maximum longitudinal shifts
relative to the substorm center longitude are -3.5 hours at By
=-4 nT and 3.5 hours at By = 4.4 nT. Thus, the change of substorm
center localization relative to midnight in the ionosphere is caused by
both the change of substorm center location in the magnetosphere and the
turn of the magnetotail relative to the X-axis.
DYNAMICS OF MAGNETIC FIELD IN THE NEAR MAGNETOTAIL DURING SUBSTORMS WITH SHARP ONSET OF EXPANSION PHASE
R.N. Boroyev (Institute of Cosmophysical Research and Aeronomy, Yakutsk, Russia)
By using satellite magnetic field measurements
it is shown that before the substorm expansion phase onset the field-aligned
currents of zone 2 type are not always observed on the geosynchronous orbits
at the midnight sector. The relationship between the appearance of the
field-aligned currents of zone 2 types before the beginning of the substorm
expansion phase and the active phase duration and the preceding magnetic
disturbance level has been found. It is found that if the expansion phase
lasts less than 11 min, the appearance probability of the field-aligned
current of zone 2 type before the substorm expansion phase onset T0
decreases. As the geomagnetic activity rises before a substorm, the probability
of the beginning of field-aligned currents before T0 increases.
These results indicate that substorms, in which the field-aligned currents
of zone 2 type before the T0 onset are absent, can be probably
developed in the distant part of the magnetotail.
DYNAMICS AND LOCAL STRUCTURE OF AURORA DURING ISOLATED SUBSTORM MARCH 23, 1998
L.L. Lazutun (Moscow State University,
Moscow, Russia; Polar Geophysical Institute, Apatity, Russia)
G.V. Starkov, A.A. Soldatov, T.A. Kornilova
(Polar Geophysical Institute, Apatity, Russia)
C.-I. Meng, D. Sibeck, Kan Liou (The
Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA)
D. Bjordal (Space physics Department,
Bergen University, Bergen, Norway)
After the ground-based TV optical observations
at Loparskaya, POLAR X-rays data and the magnetic data of the Scandinavian
chain the substorm on March 21, 1998 during pre-midnight hours were investigated.
It was found that this substorm was triggered by northward turn of Bz-component
of IMF. According to POLAR data the substorm began far eastward of Loparskaya
and the substorm onset was not accompanied by X-rays emissions over Kola
Peninsula. It is shown that the second aurora activation was caused by
coming of WTS from the East. During this activation an appearance of vortex-like
rotational auroral structures, X-rays emissions over Kola Peninsula and
fast variations of the Y-component of magnetic field were observed. Location
of westward electrojet determined by the IMAGE network was compared with
aurora dynamics. It was revealed that westward electrojet is situated poleward
of the region of auroral luminosity maximum at the Loparskaya meridian.
RAYED AURORAL STRUCTURES IN THE DAYSIDE OF THE AURORAL ZONE
V.R. Tagirov (Polar Geophysical Institute,
Apatity, Russia)
V.A. Arinin (Russian Federal Nuclear
Center, Sarov, Russia)
V.S. Ismagilov (St.-Petersburg Brunch
of IZMIRAN, St.Peterburg, Russia)
The interaction of magnetic cloud with
the Earth's magnetosphere on the basis of TV auroral observations, magnetic
ground-based and IMF data and plasma parameters of the solar wind was studied
for the time interval from 04.17 to 10.30 UT on 14.01.1988. Auroral TV
observations were carried out in Frantz-Joseph Land (Heiss Island) and
covered the whole dayside sector corresponding to the event. Auroral forms
represented very active rayed forms travelling mostly in azimuth direction
with velocities about several kilometers per second. The polar plots of
auroral motion showed the moved following to "inverse" twin-cell convection
pattern with sunward flow over the pole. We divided the whole interval
of auroral observations into three regimes depending on the characteristics
of auroral motion and solar wind parameters. The IMF Bz-component during
the whole interval was very high exceeding 18 nT whereas By-component changed
the sign at about 1.5 h later local magnetic noon at the point of auroral
observations, By was slightly positive. The first regime was characterized
by a very steep increase in solar wind dynamic pressure and as a consequence
rapid motion of auroral forms mostly in the westward direction in prenoon
sector. The second regime differed by much less dynamic pressure values
and pronounced sunward flow motion of auroral forms under positive By-component
conditions. The third regime was characterized by the turn of By-component
to the opposite direction and change of auroral forms velocity vector to
the eastward direction. Possible reasons of different behavior are discussed.
МАГНИТНАЯ БУРЯ 14-17 МАЯ 1997 ГОДА: ВАРИАЦИИ В ИОНОСФЕРЕ И УСЛОВИЯХ РАСПРОСТРАНЕНИЯ РАДИОВОЛН
Д.В. Благовещенский, В.И. Кулакова
(Санкт-Петербургский государственный
университет аэрокосмического приборостроения (СПбГУАП))
Проявления возмущений магнитосферного происхождения
в ионосфере Земли имеют достаточно сложный характер. Магнитосферные бури
и суббури вызывают резкие нарушения структуры ионосферы, создавая сложности
при передаче информации по КВ радиоканалам, особенно в высоких широтах.
Здесь еще много непонятного с точки зрения физики происходящих явлений
и мало статических экспериментальных данных на радиотрассах, поскольку
модели ионосферы и расчеты распространения радиоволн даже в средних широтах
во время возмущений не корректны, не говоря о высоких широтах.
В настоящей работе произведено сопоставление
геофизических данных, полученных с базовых центров Интернета, и параметров
радиоволн на высокоширотной КВ радиотрассе о.Хейса - Санкт-Петербург длинной
D = 2500 км для интенсивной магнитной бури 14-17 мая 1997 года. Основное
внимание уделялось особенностям поведения диапазона рабочих частот МНЧ-ННЧ
(максимальная и наинизшая наблюдаемые частоты). Показано, что этот
диапазон несет ценную информацию о динамике ионосферы. Фактически, получение
диагностических данных МНЧ и ННЧ есть метод наклонного зондирования ионосферы,
который в отличие от метода вертикального зондирования работает надежно
и в предиоды магнитных бурь. НЗИ позволяет практически без потерь информации
проследить вариации в изменениях концентрации слоя F2 ионосферы и других
параметров во время возмущений зы счет магнитной бури. Тогда как эту же
информацию по данным вертикального зондирования (ВЗ) ионосферы получить
практически без существенных потерь нельзя, поскольку из практики зондирования
известно, что наблюдается резкое уменьшение количества данных В3 ионосферы
во время достаточно возмущенных условий. С помощью диапазона частот можно
именно косвенно оценить параметры ионосферы, поскольку верхняя граница
диапазона МНЧ (максимальная наблюдаемая частота) в общем случае в
дневных условиях характеризует степень ионизации слоя F2 ионосферы.
Чем выше МНЧ, тем выше ионизация в F2-слое. В ночных условиях особенно
в возмущенное время, МНЧ может определяться спорадической ионизацией
в E-слое ионосферы. Нижняя граница диапазона ННЧ (наинизшая наблюдаемая
частота) наоборот характеризует степень поглощения в нижней области
ионосферы. Чем выше ННЧ, тем выше, на пример, концентрация в слое D ионосферы
(днем) или уровень поглощения в нижней области ионосферы (ночью).
THE PROBABILITY OF THE MAGNETOSPHERIC DISTURBANCE TRIGGER BY THE FAST IMF CHANGES
M.G. Gelberg (Institute of Cosmophysical Research and Aeronomy, Yakutsk, Russia)
It was found, that the probability of the
magnetospheric disturbance (substorm or intensification) trigger
by the By, Bz component IMF fast changes after long
period Bz<0 was less 45%. Once was smaller when the solar
wind velocity was less in spite of equal values of the electric fields
and Poitng's vector's. The difference between the mean velocity values
was equal about 100 km/s for the with trigger and without once events.
The magnetospheric disturbance initationion wasn’t observed if the solar
wind velocity was 300 km/s or less. It was noted that the without trigger
event offen coincidented with stationary magnetospheric convection or convectional
bay periods.
SUPERIMPOSED EPOCH ANALYSIS OF THE SOLAR WIND PARAMETERS NEAR THE SUBSTORM ONSET
A. A. Arykov, Yu. P. Maltsev, and I. V. Golovchanskaya (Polar Geophysical Institute, Apatity, Russia)
Temporal behavior of the solar wind parameters
during substorms has been analyzed by the superimposed epoch technique.
The substorm onsets detected by the Polar satellite were chosen as zero
time moments. An average substorm occurs under a small (~1 nT) southward
IMF component. The other parameters (velocity, density, IMF modulus) are
close to their average values. No pronounced changes of the solar wind
parameters were detected near the substorm onset. Substorms with high Kp
and AE indices are accompanied by enhanced solar wind velocities and densities.
SPONTANEOUS AND STIMULATED EVENTS IN SOC SYSTEM AND ITS ANALOGY WITH SUBSTORM ONSETS
B.V. Kozelov, T.V. Kozelova (Polar Geophysical Institute, Apatity, Russia)
The types of substorm onset stimulation
have been classified by analogy with dynamic of the model system which
has a self-organized critical (SOC) state. Spontaneous, locally stimulated,
and globally stimulated events have been considered. We suppose that the
strength of the IMF Bs determines the maximum energy, which the magnetosphere
can hold in it and the rate of energy accumulation in the magnetosphere.
In this model the energy which may be emitted during substorm depends on
the history of energy accumulation. The statistical results about IMF Bz
features near substorm onset have been explained, but it was found that
such results cannot be used as a substantiation of spontaneous or stimulated
nature of substorm onsets. It was found that the probability of onset stimulation
must depend on value of IMF Bz deviation. It was noted that statistical
investigation of SOC system may lead to erroneuos deductions.
ДВА ГЛАВНЫХ ГЕОЭФФЕКТИВНЫХ ПАРАМЕТРА СОЛНЕЧНОГО ВЕТРА, БУРИ И СУББУРИ
Н.С.Зарецкий (Институт космофизических исследований и аэрономии, Якутск)
Анализируются относительные степени влияния
скорости солнечного ветра и северо-южной компоненты ММП на сравнительные
частоты появления магнитных бурь и суббурь. Исходными данными для анализа
явились известные каталоги геомагнитных бурь Афанасьевой - Шевнина, магнитных
суббурь на ст. Львов Литинского и каталог Кинга за совпадающие 1965-1975
гг. Установлено, что отношение годовых количеств магнитных бурь к числу
суббурь растет с увеличением частного от числа часовых значений скорости
солнечного ветра и южной компоненты ММП более 500 км/с и 1 нТл. Это свидетельствует
в пользу существующего, но не общепринятого мнения, что причинами магнитных
бурь и суббурь являются, главным образом, скорость солнечного ветра и южная
компонента ММП, соответственно.
LOCAL CHANGE OF FIELD ALIGNED CURRENT INTENSITY BEFORE THE BREAK-UP ONSET
V.A. Velichko, R.N. Boroyev, D.G. Baishev
(Institute of Cosmophysical Research and Aeronomy, Yakutsk, Russia)
The dynamics of current systems during
a substorm has been studied by the ground-based data of the longitudinal
magnetovariational station chain. The field-aligned current system appearing
at the meridian of the expected substorm center formation 10-20 min before
the break-up has been brought up by the processing results of geomagnetic
variations. The field-aligned currents flow into the ionosphere westward
relative to the future substorm center and flew out eastward of it. The
longitudinal sizes of the field-aligned current system varied from 20 degrees
to 50 degrees. The preliminary phase was completed by the change of direction
of field-aligned currents to the opposite one. The obtained results confirm
the idea that the formation of the substorm center is associated with the
appearance of the Birkeland's current loop on the preliminary substorm phase.
AURORAL TV DATA DYNAMICS AND VORTICITY
O.I. Kornilov, M.I. Pudovkin (Physical Institute, St.Petersburg State University, St.Petersburg, Russia)
Investigation of auroral TV data provide
us a wide spectra of magnetosphere and ionosphere parameters. In particular,
from dynamics of auroral luminosity it's possible to derive the magnetic
reconnection speed, the electric field intensity and the vorticity in the
magnetospheric plasma. Some characteristics of auroral vorticity (the shape
of vortices, the sense of rotation, their power spectra) allow one to determine
the parameters of the ambient plasma, the nature of the vorticity source
and the physical mechanisms exciting the turbulence. Fully automatic software
for calculating of auroral dynamics was developed. Using this software
we have analysed TV data from stations Porojarvi and Lovozero. Some features
of the derived auroral vorticity are presented.
THE INVESTIGATION OF AURORAL SUBSTORM FROM CUTLASS RADAR DATA AND OPTICAL OBSERVATIONS
G. Starkov (Polar Geophysical Institute,
Apatity, Russia)
R. Pellinen, T. Pulkkinen (Finnish
Meteorological Institute, Helsinki, Finland)
A. Fabirovsky, M. Uspensky (Murmansk
State Technical University, Murmansk, Russia)
P. Eglites, H. Opgenoorth (Institute
of Space Physics, Uppsala, Sweden)
It is shown that the CUTLASS radar system
gives us the important information about the plasma dynamics during the
development of auroral substorm. On the November 17, 1996, the Iceland
CUTLASS radar had been registering the signal from the polar cap before
the beginning of substorm, which was, probably, connected with the band
of diffuse luminosity, that borders auroral oval from the highlatitudinal
side. The beginning of the preliminary phase was discovered by the Finnish
radar first. At 18.50 UT the Finnish radar registered the beginning of
equatorward motion in the F-layer 7-8 minutes after the turning of Bz-component
of IMF towards south. The velocity of this signal corresponds to azimuthal
electric field 20 mV/m. The active phase of substorm begins after turning
of Bz towards north, i.e. this distribution is the stimulated substorm.
The electric field during active phase, that is calculated from auroral
motion, increases up to 40 mV/m. The electric field, that was measured
by EISCAT, has the maximum during the preliminary phase and abrupt decrease
after the active phase beginning due to the increase of ionospheric conductivity.
During the active phase the Iceland radar observes the signal, that appears
near the polar boundary of the auroral oval, moves equatorward across the
oval and disappears into the belt of diffuse luminosity.
RELATION OF THE POLAR CAP VOLTAGE TO THE SOLAR WIND PARAMETERS AND STORM INTENSITY
E.Yu. Feshchenko (Institute of Physics,
St-Petersburg State University, St-Petersburg)
Yu.P. Maltsev (Polar Geophysical Institute,
Apatity)
We have processed electric field observations
detected by the Dynamics Explorer 2 satellite and obtained several hundred
values of the electric potential difference between the dawn and dusk sides
of the polar cap. Hourly-averaged solar wind parameters and geomagnetic
indices have been used for studying statistical relations. The potential
difference appeared to depend on the IMF southward component and solar
wind velocity both for the current and previous hour. The growth of the
magnetic storm-time depression linearly depends on the potential difference.
HIGH LATITUDE PC5-6 RANGE GEOMAGNETIC PULSATIONS AND IMF VARIATIONS DURING STRONG MAGNETIC STORM ON FEBRUARY 21,1994
N.G. Kleimenova, O.V. Kozyreva (Institute
of the Earth Physics, Moscow, Russia)
J.-J. Schott (Ecole et Observatoire
des Sciences de la Terre, Strasbourg, France)
M. Bitterly (Institute de Physique
du Globe, Paris, France)
P.K. Ivanova (Geophysical Institute,
Sofia, Bulgaria)
We have analyzed the long period geomagnetic
pulsations in the frequency range of 1-6 mHz as a response to the interplanetary
magnetic cloud that made an impact on the Earth magnetosphere and triggered
the strong magnetic storm on February 21,1994. It was found that SSC at
09.01 UT as well as the initial phase of this storm were accompanied by
geomagnetic pulsations with maximum amplitudes near the dayside polar cusp
at the frequencies less than 2 mHz (ipcl-type). The dynamic spectra of
these pulsations were similar to the spectra of IMF variations, particularly
to the Bx. We speculated that ground ipcl pulsations could be results of
the interplanetary hydromagnetic waves penetrating into the Earth magnetosphere.
Two interesting intervals of this magnetic storm were also analyzed: one
(~13-14 UT) - with very strong (up to ~100 nPa) solar wind dynamic pressure,
and the second (~15 UT) - with very high values of B IMF (up to ~70 nT),
that is, with strong magnetic pressure. Under the first conditions the
burst of 1-3 mHz geomagnetic pulsations were observed only near the dayside
polar cusp, however, under the second conditions the same frequency range
geomagnetic pulsations were detected in the closed magnetosphere. The resonance
Pc5 pulsations of 3-5 mHz have been observed during both intervals with
maximum of the intensity in the afternoon.
ANALYSIS OF THE SOLAR WIND - MAGNETOSPHERE COUPLING BY THE PREDICTION FILTER TECHNIQUE
V. V. Shelomentsev (Institute of Solar-Terrestrial Physics, Irkutsk, Russia)
Given are the results of application of
the prediction filter technique to the solar wind - magnetosphere coupling
problem. Dependence of the filters' forms on different external and internal
conditions (intervals of prolonged northward and southward IMF, isolated
substorms and the long substorm sequences) is analysed. The results support
the suggestion about the non-linearity of the magnetospheric response to
changes of the external conditions and testify of the importance of the
inner state of the magnetosphere for the development and the energetics
of a single disturbance. Using the obtained filters, the fast and the delayed
responses of a separate magnetospheric parameter have been picked out,
associated with the near and the far prehistories of the external conditions
and caused by the two kinds of processes (driven and unloading), respectively.
Temporal interval of the near prehistory inferred from the form of the
filter is the time it takes for solar wind to pass the length of an open
magnetospheric tail. Estimates of the "effective" tail length are in good
agreement with the similar ones obtained from the theory of an open magnetosphere
and the satellite observations in a tail. It was shown that both kinds
of processes are important for the substorm development, but they differ
greatly in their manifestations in the concrete magnetospheric parameter.
It appears that the magnetospheric electric circuit contains the non-linear
elements. The analogue of this circuit gives an insight into the observed
regularities of the electric fields, currents, and energetics during a
substorm development. This study is supported by the RFBR grant 98-05-65120.
AURORAL DISTURBANCES DURING THE PROPAGATION OF THE EARTH THROUGH MAGNETIC CLOUDS
M.G. Gelberg, S.Z. Kershengoltz (Institute of Cosmophysical Research and Aeronomy, Yakutsk, Russia)
Types of long auroral disturbances (LADs)
observed during the propagation of the Earth through magnetic clouds (MCs)
have been correlated with the classes of MCs. Dependences of average and
maximum values of AE-indices on characteristics of MC have been investigated.
It is shown that SN-clouds with compressed front ends produced the first
type of LAD (9 events from 10 ones) and the third type of LAD in one event.
LAD of the first type has been observed in three events from 5, of the
third type in one event and of the fourth type in one event, when no compression
exists. NS clouds produced on the Earth the first type of LAD (4 events
from 8 ones), the third type in three events and the fourth type in one
event. It is found established that the auroral disturbance intensity did
not depend on the solar wind speed, V, IMF Bz and the y-component
Ey of electric field, if the ends of clouds with Bz
<0 are compressed. When no compression exists, the correlation coefficients
between V, Bz, Ey and AE are 0.39, 0.57 and 0.72,
respectively. For the two groups of clouds the LAD intensity increases
as the duration of Bz <0 increases. It is noted that LADs
of the second type of the small and mean intensity are developed in the
auroral zone after the propagation of the Earth through the clouds with
non-compressed back ends (13 events from 16).
DISCRETE AURORAL ARC DYNAMICS IN THE BULGE REGION AT THE BREAKUP AS OBSERVED AT HIGH-LATITUDE STATION LONGYERBYEN
Y.V. Bogdanova, V. S. Semenov (Physical
Institute, St.Petersburg State University, St.Petersburg, Russia)
K. Kauristie (Finnish Meteorological
Institute, Helsinki, Finland)
We present the results of investigation
of the auroral discrete arc motion during the expansion phase of a substorm,
as observed at high-latitude station Longyearbyen (geographical latitude
78,20). All-sky camera data recorded during a period of 4 years (1996,97,98,99)
were analysed. It turned out, that at high-latitudes the dynamics of discrete
arcs have the following tendency: while the polar boundary of auroral oval
jumps polewards, almost all separate discrete arcs move equatorward after
their formation. This result confirms new theory of auroral arc generation
presented by Semenov et. al. According to this theory an auroral arcs are
caused by the arrival of a shock waves into the ionosphere. These shock
waves are generated during reconnection pulses in the magnetotail current
sheet. This model predicts the same dynamics of discrete aurora at high
latitudes, as observed in Longyearbyen.
BEHAVIOR OF DIFFUSE LUMINOSITY DURING PRELIMINARY SUBSTORM PHASE
T.A. Kornilova, I.A. Kornilov (Polar Geophysical Institute, Apatity, Russia)
The behavior of diffuse luminosity at the
preliminary phase of substorm has been investigated after the TV auroral
data. It was found out that the interchange of diffuse luminosity isotropization
and appearance of structures inside it with a period ~ 10 minutes under
the moderate magnetic activity and about ~15 minutes under the weak one
took place. Such structures may be black bands or pulsating arc-like filaments
unmoved as well as drifting poleward or equatorward. It is shown that about
~5 minutes before the breakup onset, pulsating structures appear inside
diffuse luminosity and 2-5 minutes after that diffuse luminosity becomes
homogeneous, the southern boundary at this time being less distinct. Variations
of diffuse luminosity brightness with period ~15-20 minutes are observed.
The appearance of the gap in luminosity ~ 5 minutes before the breakup
onset equatorward from the place where breakup should start was revealed.
In the case when the gap is situated inside diffuse luminosity the one
behavior of poleward and equatorward of the gap is different.
INFLUENCE ON GEOEFFECTIVE MAGNETIC CLOUD CHARACTERISTICS OF THEIR INTERACTION WITH INTERPLANETARY SPACE AND OF CYCLIC SOLAR ACTIVITY VARIATIONS
M.G. Gelberg (Institute of Cosmophysical Research and Aeronomy, Yakutsk, Russia)
Estimations of the relative contribution
to the total dispersion of geoeffective magnetic cloud characteristics
of their compression by interplanetary plasma flows and solar activity
variations have been found. It is shown that compression effects of magnetic
clouds account for about 50% of the total dispersion of the IMF Bz
and electric field Ey, and cyclic variations of solar activity
account for about 15%. It is established that the duration \delta Ts
of the southern orientation of Bz in the magnetic clouds depends
on the interaction of clouds with interplanetary space only in the solar
activity minimum. Variations of solar activity account for about 10% of
the total dispersion \delta Ts. It is noted that the comparative
analysis of the magnetic cloud geoefficiency of different polarity must
be carried out taking into account the solar activity cycle epoch. It is
argued that the geoeffectiveness prognosis of the SN magnetic clouds are
more reliable than NS one.
EVIDENCES FOR CLOSE RELATIONSHIP BETWEEN Pc1 PULSATIONS AND LOCALIZED PRECIPITATION OF THE RING CURRENT PROTONS
T.A. Yahnina, A.G. Yahnin (Polar Geophysical
Institute, Apatity, Russia)
J. Kangas, J. Manninen (Sodankyla Geophysical
Observatory, Sodankyla, Finland)
Using the low-altitude NOAA satellite data
we for the first time found and described a pattern of proton precipitation,
characteristics of which closely corresponded with those for the Pc1 pulsations.
The pattern is characterised by the burst of both precipitating and locally
trapped energetic protons within the zone of anisotropic fluxes. The bursts
are localised (~1° of corrected geomagnetic latitude); most of events are
found within the range of 61°-67° corrected latitude; they appear mainly
during the recovery phase of geomagnetic storms, and their occurrence rate
is maximal on the day side. The comparison of these specific proton bursts
detected in the ionosphere with Pc1s observed in Sodankyla Geophysical
Observatory, Finland has been performed for the whole year 1996. We found
that the Pc1s on the ground can be observed at any MLT distance from the
satellite detecting the precipitation burst, but the probability of the
intense Pc1 observations strongly decreases with increase of the distance.
We found that frequency of the ground Pc1 decreases with the increase of
the proton burst latitude. In cases of multiple-band Pc1 the satellite
often measures multiple bursts at different latitudes. These facts mean
that considered proton bursts do mark the source of Pc1s. These findings
strongly confirm the idea that Pc1 pulsations are the result of ion-cyclotron
instability of the ring current ions.
NATURE OF TWO TYPES OF MAGNETOSPHERE PERTURBATIONS AS INTERFRACTALIC SPECTRA RESONANCES
L.P. Shadrina, V.G. Vasilyeva (Institute of Cosmophysical Research and Aeronomy, Yakutsk, Russia)
An attempt is made to answer a question
what is the nature of division of all geomagnetic storm situations in two
quality types refering to its main phase AE-index integral. Furthermore
a question why those characteristics have no intermediate values and auroral
states have arisen from the previous analysis of auroral dynamics subject
to this deferent types of magnetic storms.
Presented investigation is accomplished
by terms of statistical consideration of totality of geomagnetic disturbances
as the virtual ensembles of the magnetosphere states. The fractal model
of classical ensemble was suggested earlier on the base of global geomagnetic
statistics data. On the other hand the mixed distributions were interpreted
as resonance effect between two states of magnetosphere. These brought
the investigation to temporal spectra of every level of magnetic activity.
We suppose that it is possible to show that two types of magnetospheric
storms are the sequences of regular combinations of those spectra. The
spatio-temporal resonance taking place as an absolute content of real discretization
of energetic dissipation process is to be noted.
COMPARISON OF GEOEFFICIENCY OF VARIOUS SOLAR WIND PARAMETERS
V. Golovchanskaya, Yu.P. Maltsev (Polar Geophysical Institute, Apatity)
Relation of AE and AL indices to several
hourly-averaged solar wind parameters has been statistically studied for
the period of 28 years. The indices are satisfactorily described by a linear
combination of the IMF southward component Bs, solar wind velocity V, and
proton mass flux nV for the previous hour. The effects of the IMF z component
variability, IMF modulus, and epsilon parameter estimated together with
the effects of Bs, V, and nV appeared to be insignificant. Study of the
indices within several ranges of V and Bs has shown that the relative contribution
of the solar wind electric field VBs to the geomagnetic activity is most
likely small as compared with the contribution of the linear combination
of V and Bs.
DO THE OBSERVATIONS CONFIRM THE HIGH SPEED FLOW BRAKING MODEL FOR SUBSTORMS?
A.G. Yahnin, I.A. Kornilov, T.A. Kornilova
(Polar Geophysical Institute, Apatity, Russia)
V.A. Sergeev (Institute of Physics,
University of Saint-Petersburg, Saint-Petersburg, Russia)
A.T.Y. Lui, K. Liou, C.-I. Meng (The
Johns Hopkins University, Applied Physics Laboratory, Laurel, MD, USA)
A. Pajunpaa (Finnish Meteorological
Institute, Helsinki, Finland)
We studied a few cases when Geotail satellite
situated in the mid-tail was mapped close to the meridian of the ground-based
all-sky TV cameras observing the auroral breakups. Localisation of auroral
events within the field of view of ground-based stations and with respect
to Geotail position has been controlled with the Polar UVI data. High-speed
(500-700 km/s) Earthward plasma flows have been seen in the plasma sheet
some 10-20 minutes before some of these breakups, and these cases have
been carefully investigated. From the analysis of the timing and plasma
flow front propagation we concluded
that in considered cases there was
no causal relationship between fast plasma flows and breakups. In addition,
we checked for the possible auroral precursors, which may be expected just
poleward of the breakup location in association with suggested high-speed
flows. We searched for either north-south directed auroral structures or
some auroral forms moving equatorward just before the first auroral arc
brightening. Because such structures might be subvisual, different methods
of the TV data processing were used to detect the weak auroras. Our analysis
did not show any auroral precursors. Thus, our observations failed to confirm
the model of substorm onset based on the braking of the high-speed Earthward
plasma flow.
VARIATIONS OF ENERGETIC ELECTRON PRECIPITATIONS DURING A SOLAR ACTIVITY CYCLE
V.A. Kuzmin (Institute of Cosmophysical Research & Aeronomy, Yakutsk, Russia)
Variation of the appearance frequency of
energetic electron precipitations (Auroral Absorption, AA) registered with
the riometer (32 MHz) at Tixie station for 1986-1996 are studied. The frequency
of energetic particle precipitations equals to the number of hours during
a day, when the amplitude and duration of absorptions are more than 0.3
dB and 10 min, respectively. It is shown that a maximum of the precipitations
frequency delays four years relative to the maximum phase of Wolf numbers
(1990) and falls on the decay phase of the 22 nd solar activity cycle.
The amplitude variations of the frequency electron precipitations in 1994
is about 70% relative to the minimum value in 1987. A contribution of PCA
events to the total frequency of energetic particle precipitations (AA+PCA)
is 20% in 1989, 7% in 1990 and 12% in 1991. The probable reason of the
increase of the AA appearance frequency in 1992-1994 are CME events and
high-velocity solar wind streams from coronal holes. The energetic electron
precipitation frequency has the largest correlation with the solar wind
velocity and also with its dynamical and thermal pressure.
THERMAL PLASMA CHARACTERISTICS FROM GROUND BASED AND SATELLITE MEASUREMENTS ON BOARD INTERBALL 2 AND AKTIVNY DURING SAR-ARC EVENTS
V.L. Khalipov 1, Yu.I. Galperin
2, V.V. Afonin
2, V.N. Alexeev 1, I.B.
Ievenko 1, A. E. Stepanov 1
1 Institute of Cosmic Research
and Aeronomy, Yakutsk, Russia
2 Space Research Institute,
Moscow, Russia
Ground based optical observations of the
SAR-arcs and ionospheric parameters at meridian of Yakutsk (130 deg. E,
2.5 < L < 4.2) in 1989 - 1998 and simultaneous measurements of the
ion density and electron temperature on board INTERBALL 2, AKTIVNY and
APEX satellites are analyzed. The data show that in the period of moderate
geomagnetic activity SAR-arc appeared in the region of the Polarization
Jet (PJ, or SAID) in the dusk sector at L ~ 3.5 - 4.0. Strong local electric
field of the PJ (~ 100mv/m) is a powerful source for heating of charged
and neutral particles in the SAR-arc region. When magnetic storm develops,
the observed PJ and SAR-arc move to L ~ 2.8 - 3.0. After midnight the SAR-arc's
magnetic flux tubes containing hot ions convect to inner magnetosphere
with speed ~ 30 - 50 m/s. The temperature peak above the SAR-arc is much
more pronounced at altitudes < 0.5 Re than at altitudes 1 Re.
COMPARATIVE ANALYSIS OF AKR AND AURORA DYNAMIC CHARACTERISTICS: INTERBALL-2 AND POLAR MEASUREMENTS
A.A. Rusanov 1, T.V. Romantsova
1, M.M. Mogilevsky
1, J.Hanasz 2, V.N.
Nazarov 1
1 Space Research Institute
(IKI RAN), Moscow, Russia
2 Space Research Center
(CBK PAN), Torun, Poland
Fluxes of down-going energetic electrons
are well known to be the primary sources of Auroral Kilometric Radiation
(AKR) and aurora. The result of high time resolution analysis of AKR spectral
characteristics and its connection with aurora intensity dynamics are presented.
AKR spectra and images of aurora were obtained simultaneously onboard INTERBALL-2
satellite (experiment POLRAD) and POLAR satellite (experiment UVI) respectively.
The special software was created for comparative analysis. This kind of
analysis was made for substorm periods.
Some peculiarity of AKR spectra during
explosion phase of substorm was found: sharp increase of spectral components
at the highest frequencies. It means that intensification of aurora is
connected with acceleration region expansions (AKR source). A physical
mechanism of AKR source dynamics is discussed.
МОНИТОРИНГ КОСМИЧЕСКИХ ЛУЧЕЙ В РЕАЛЬНОМ ВРЕМЕНИ И ВОЗМОЖНОСТЬ ЕГО ИСПОЛЬЗОВАНИЯ ДЛЯ ПРОГНОЗА БОЛЬШИХ МАГНИТНЫХ БУРЬ.
А.В.Белов, Е.В.Вашенюк, Р.Т.Гущина, Е.А.Ерошенко,
А.Б. Струминский, В.Г. Янке
(Институт земного магнетизма, ионосферы
и распространения радиоволн РАН, Троицк,)
Российские станции космических лучей Москва
и Апатиты уже долгое время представляют вариации космических лучей в реальном
времени в Internet и эти данные стали одним из ресурсов космической погоды.
Космические лучи (и особенно их анизотропия) чутко реагируют на крупномасштабные
изменения в межпланетной плазме и могут дать дополнительную информацию
об электромагнитном состоянии околоземного космического пространства. На
этом основаны индексы возмущенности космических лучей, несколько
вариантов которых появились в последние годы. Оперативную диагностику можно
осуществить, если данные достаточно большого числа станций в широком диапазоне
широт и долгот удастся объединять и анализировать в реальном времени. Такую
задачу ставит международный проект "Космический корабль Земля", в котором
участвуют российские высокоширотные станции. Такая оперативная диагностика
должна стать основой прогнозирования крупных магнитосферных возмущений
с привлечением вариаций космических лучей.
POLEWARD PROPAGATING MULTIPLE ARC-LIKE FORMS IN PULSATING AND DIFFUSE AURORAS: IONOSPHERIC TRACE OF A SUBSTORM TRIGGER?
V. Safargaleev, S. Osipenko (Polar Geophysical Institute, Apatity, Russia)
We report several cases of TV- observations
of the multiple-auroral-arc-like forms observed between two successive
breakups when pulsating or diffuse auroras stayed on the sky after the
first onset. The events represent several passes of the strips of enhanced
luminosity through the background auroras toward the auroral oval pole
boundary. The forms are faint and also masked by background luminosity,
so the keogram analysis is the only way to study their dynamics. The strip
velocity is of about 0.3 km/s at ionospheric altitude, the repetition period
is 2-5 minutes. We assume those events to be an auroral manifestation of
the MHD-waves exited in the magnetosphere during sudden changes of the
solar wind dynamic pressure. The simple model for the waves propagating
in the medium with smooth plasma gradient (internal edge of the magnetotail
plasma sheet) is discussed. We think that the luminosity variations in
a single auroral arc just before the substorm onset (pseudobreakup event)
may be also caused by the propagation of these waves in the plasma sheet
through the arc generator region. The phenomenon is discussed in the context
of the substorm triggering problem.
ПРЯМОЕ УСТРАНЕНИЕ ВСЕХ ВИДОВ ГЕОМЕТРИЧЕСКИХ ИСКАЖЕНИЙ ТЕЛЕВИЗИОННЫХ ИЗОБРАЖЕНИЙ ПОЛЯРНЫХ СИЯНИЙ.
В.А. Аринин (Российский федеральный
ядерный центр, Саров, Россия)
В.Р. Тагиров (Полярный геофизический
институт, Апатиты, Россия)
Предлагается метод коррекции геометрических позволяющий за один проход устранить ошибки в позиционировании (наклон и ориентацию) и оптическую дисторсию при наблюдениях полярных сияний телевизионными камерами всего неба. Это делает возможным триангуляцию авроральных и других оптических явлений и проекцию их на поверхность Земли. Применение для коррекции раскраски Гуро (билинейной интерполяции) позволяет достичь субпиксельной точности при преобразовании изображений и экстраполировать матрицы коррекции до горизонта без существенных потерь точности.