I.M. Podgorny (Institute for Astronomy, Moscow, Russia )
A.I. Podgorny (Lebedev Physical Institute, Moscow, Russia )

Plasma clouds (or jets) ejected from the Sun can produce magnetic perturbations in the Earth magnetosphere. Several attempts to simulate magnetosphere reaction have been published. In our recent works it has been shown that plasma can be ejected from the sun because of acceleration in the coronal current sheets or local chromospheric heating during a solar flare. Here we present results, which permit to understand some phenomena of solar-terrestrial physics, including plasma clouds dynamics. The numerical solutions of 3D MHD resistive equation for compressible plasma are carried out. The PERESVET code of new generation is used. Anisotropy of the thermal conductivity in the magnetic field are taken into account. These results obtained for different angles between magnetic field and plasma bulk velocity. It is shown that magnetosonic and Alfven waves ahead of the jet front propagation are demonstrated. They create waves of plasma compression and rarefaction respectively. The comparison these results and data obtained at zero magnetic field, demonstrate the importance of thermal conductivity reduction across the field lines. Four main phases of jet motion are investigated: a) high-beta plasma expansion; b) plasma motion in the magnetic cavity at the equilibrium between plasma and magnetic pressures; c) plasma motion across the magnetic field when FAC generation occurs and jxB force produces deceleration; d) equilibrium violation between Lorenz and electrical forces produces jet deviation. a) -c) phases are simulated in 3D MHD resistive approximation. It is shown the important role of Hall electric field in the c) phase. The dependence of jet dynamics on the angle between velocity and magnetic field vectors and on Mach numbers is demonstrated. The effect of electric field in d) phase is estimated. The results of simulations are compared with the results of measurements in magnetospheric active experiments including barium clouds release. The plasma jet injection in the magnetosphere from the tail is another example high-beta plasma jet interaction with low-beta plasma.
 
 
 
 

ABOUT POSSIBILITY OF SOLAR FLARES AND CME EJECTION DUE TO A NEW MAGNETIC FLUX EMERGENCE IN THE ACTIVE REGION

I.M. Podgorny (Institute for Astronomy, Moscow, Russia )
A.I. Podgorny (Lebedev Physical Institute, Moscow, Russia )

There are many observational data that demonstrate solar flare appearance high in the corona above an active region. Previous MHD simulations demonstrated the possibility of a current sheet creation in the vicinity of a singular line. Decay of such a current sheet produces the flare and/or transient ejection. In some case creation of the solar flare occurs after emergence of a new strong magnetic flux in a rather simple active region which is doubtful possess a singular line. Here we consider the scenario of a current sheet creation at floating up a new magnetic flux from the photosphere with magnetic field direction opposite to the old magnetic field. This scenario is simulated in the numerical MHD experiments. For solving resistive MHD equations for compressible plasma PERESVET code is used. Anisotropy of thermal conductivity in the magnetic field is taken into account. Space distributions of plasma parameters for different moments of time are presented. It is shown that the vertical current sheet is created. The energy accumulated in the magnetic field of the current sheet can be order of 1032 erg. After current sheet creation, plasma is accelerated along the sheet due to magnetic line tension, and full mass of plasma in the sheet decreases. The current sheet becomes thinner and thinner. Fast reconnection leads to plasma depletion near the current sheet boundary. The sheet instability manifest itself, and strong plasma ejection from the corona (CME) takes place. When the current sheet thickness is restricted by the step of integration, the calculations become not correct. Restrictions of numerical method at current sheet instability investigation and perspective of more detailed calculations are discussed.
 
 
 
 

ЭФФЕКТИВНЫЕ ЖЕСТКОСТИ ОБРЕЗАНИЯ ВЕРТИКАЛЬНО И НАКЛОННО ПАДАЮЩИХ КОСМИЧЕСКИХ ЛУЧЕЙ НА РАЗНЫХ ШИРОТАХ

О.А. Данилова, М.И. Тясто (СПбФ ИЗМИРАН, С-Петербург)

Рассчитаны эффективные жесткости обрезания вертикально и наклонно падающих космических лучей в магнитном поле спокойной магнитосферы Цыганенко 89. Проведен анализ их поведения на различных широтах (в интервале от 44С.Ш. до 53 Ю.Ш.).
 
 
 
 

HELIOSPHERIC PLASMA AND MAGNETIC FIELD DYNAMICS DURING THE RISING PART OF THE 23-RD SOLAR CYCLE: COMPARISON WITH PREVIOUS CYCLES

A.V. Dmitriev, A.V. Suvorova, I.S. Veselovsky
(Skobeltsyn Institute of Nuclear Physics Moscow State University, Moscow, Russia)

Running averages of the solar wind and interplanetary magnetic field parameters are calculated and investigated together with the solar activity characteristics. Time-epoch comparison analysis of time profiles of the solar activity and heliospheric parameters shows that their current dynamics is differ from rising phase of the 22-nd and 21-st solar cycles and similar to 20-th solar cycle. We have also found a specific hysteresis behavior when solar wind energy flow S is plotted against the sunspot number W during 20-22 solar cycles. Based on these finding and using measured heliospheric parameters during the rising phase of the current 23-rd solar cycle we are able to present some quantitative estimates of the expected solar wind energy flow for the period of time after the solar maximum. The hysteresis branch of current solar cycle has a tendency to simplify to the rising branch of 20-th solar cycle. Therefore we may meet that the 23- rd solar cycle will be similar to the 20-th one. Possible geophysical consequences are discussed.
 
 
 
 

SOURCE SPECTRA OF RELATIVISTIC SOLAR PROTONS IN THE GLE OF 29.09.1989 OBTAINED FROM NEUTRON MONITOR DATA

E.V. Vashenyuk, V.V. Pchelkin (Polar Geophysical Institute, Apatity, Russia)

The Ground Level Enhancement (GLE) caused by relativistic solar protons of 29.09.1989 was the most powerful for the past 44 years and have been widely discussed. As is known it consisted of two consecutive increases: the prompt impulsive one with a hard energetic spectrum and the softer delayed increase with gradual intensity profile. Using the modeling technique the source spectra of relativistic protons on the sun were calculated from the neutron monitor observations. These spectra were compared then with calculated ones for known acceleration mechanisms. Two of them are suggested: the acceleration by an electric field at initial phase of the event and the stohastic acceleration in turbulent plasma during the second increase. Probable scheme of the generation process related with a CME eruption is presented.
 
 
 
 

VARIATIONS OF PRIMARY SOLAR PROTON PARAMETERS IN THE 29.09.1989 GLE STUDIED BY MODELING OF GROUND LEVEL INCREASES

V.V. Pchelkin, E.V. Vashenyuk, L.N. Zapankova (Polar Geophysical Institute, Apatity, Russia)

The event on September 29, 1989 was characterized by an extreme variability of increase profiles on the worldwide neutron monitor network. It was connected to strong variations of the solar cosmic ray fluxes in interplanetary space. For a detailed study of these variations the primary solar proton characteristics under the data of ground based observations have been determined. The technique included the trajectory calculations of solar protons in a model geomagnetic field, barometric correction of the neutron monitor data, and solution of an inverse incorrect problem by methods of optimization. The parameters of primary of solar proton fluxes energetic spectra, pitch-angle distributions and anisotropy axis directions in 11 instants have been obtained to restore a fine structure of their variations in interplanetary space.