HAL Id: jpa-00219343
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Submitted on 1 Jan 1979
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SOME PROPERTIES OF INTERACTION OF MAGNETIC PISTON WITH NON-MAGNETIZED
PLASMA
N. Koshilev, N. Strokin, A. Shisko
To cite this version:
N. Koshilev, N. Strokin, A. Shisko. SOME PROPERTIES OF INTERACTION OF MAGNETIC PISTON WITH NON-MAGNETIZED PLASMA. Journal de Physique Colloques, 1979, 40 (C7), pp.C7-721-C7-721. �10.1051/jphyscol:19797349�. �jpa-00219343�
JOURNAL DE PHYSIQUE CoZZoque C7, suppZ6ment au- n 0 7 , Tome 40, J u i Z Z e t 1979, page ~ 7 - 721
SOME PROPERTIES OF INTERACTION OF MAGNETIC PISTON WITH NON-MAGNETIZED PLASMA
N.A. Koshilev, N.A. Strokin and A.A. Shisko.
S i b i z m i r , I r k u t s k 33, P.O. Box 4, U.S.S. R.
When studying phenomena with a burst nature occurring in the solar and near- terrestrial magnetospheric plasma, of in- terest are experiments simulating indivi- dual fragments and processes accompanying such phenomena. In particular, of crucial importance are the characteristics of cur- rent sheets arising when plasma is affec- ted by rapidly increasing magnetic fields.
A large number of experiments on transver- sal shock waves propagating in a rarefied plasma with a frozen-in magnetic field Ho have shown that both structure and proper- ties of such perturbations are determined largely by dissipative processes occurring as a result of development on the front of small-scale instabilities (Buneman, ion- acoustic, etc.). Transversal shock waves at
4.z U
4Mer"3 (U-shock wave velocity,-Alfven velocity in the unper- turbed plasma) have a width of A w f ~ d ~ p C
4meZ r
-
(
rJpe
=fF
-Langmuir frequency) andheat predominantly the plasma electron component.
If the action time of current on plasma is less than the time necessary for the development of Small-scale instabilities, laminar structures (4"- C
"'P. ) are observed,
With an increase of the initial field (Ho= O,no- 10 c ~ n - ~ ) 13 in the current sheet
electron component heating and are chara c- terized by properties similar to those found in theory and experiments for shock waves with M 4 Mc,
.
With a decrease i n ini- tial density (at a fixed amplitude of the piston ( z 5 1 3 0 0 ~ ) and a velocity of field increase on the plasma boundary (4.3'10 9 G/sec), due to an increase in current she- et velocity U, the time of plasma being in the transition region tn falls and when it becomes less than the tirae nece-ssary for instability excitation a quasi- stationary current sheet with a width of
C
A~'"zi*+ with parameters&=
me= u ~ ~ ~ ~ ,
+q.
% f indicating a full (A HI m; Ureflection of the particle flux, Before the magnetic piston, there is a sharp jump of the potential with a spatial width of A ~ = S O ' ~ ~ ~ & ~ ~ C ( L I ~ which can be linked with the formation under conditions of anomalous ion viscosity of a front of the turbulent electrostatic shock wave, A de- tailed study of processes in the reflec- ting current sheet is difficult because of small typical size ( ~ ~ - 1 0 - ~ c r n ) howe- ver analysis of energy spectra of ions moving at various angles to front plane permits qualitative assumptions about the character of processes and comparison with other results.
turbulent processes develop which lead to
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:19797349
