XXXVI international conference on plasma physics and CF, February 9 – 13, 2009, Zvenigorod.
SWIFT IONS STOPPING IN FULLY IONIZED PLASMA WITH ARBITRARY DEGREE
OF ELECTRON GAS DEGENERATION
*
S.Yu. Gus`kov, D.V. Il`in, *V.B. Rozanov, V.E. Sherman
St.-Petersburg Institute of Machine Building, St.-Petersburg, Russia,
sherman@VS8325.spb.edu
*
P.N. Lebedev Physical Institute RAS, Moscow, Russia, guskov@sci.lebedev.ru
One of possible ways of ICF realization is use of ion beams as the basic drivers for target
compression or additional drivers - in the fast ignition scheme. Under the process of ions stopping
in a target parameters of electronic gas in plasma may be ranged from absolutely degenerated up to
Maxwellian gas that affect significantly the process of beam energy transfer to a target.
In our previously papers a method of calculation of energy losses of fast non-thermal particles
with the fixed charge was developed [1], and also the model was proposed for an estimation of
velocity dependence of fast ion’s effective charge Zeff(u) in plasma with arbitrary ratio between
Fermi energy EF and temperature T of plasma electrons. The corresponding analytical
approximation Zeff=Z (u/Z2/3, T/Z4/3, EF/T) was received [2]. With the help of this technique it is
possible to carry out calculations of stopping cross section of fully ionized plasma for nonrelativistic swift heavy ions.
The calculations submitted in the present work, are performed for two types of ions from various
sections of a periodic table of elements, namely: krypton 84Kr36, as characteristic example of an
element from middle of the table with A ~100, and lead 208Pb82, as example of heavy ions with A
200. The temperature of dense plasma with 100g/cm3 was changed in a range from 100eV up to
10keV, energy of ions - from values near to thermal, up to  MeV/n. For comparison with
existing experimental data of ion energy loss in gas discharge plasma the stopping cross sections
were calculated for low density plasma with ne1016 1019 cm-3. The obtained values stopping cross
section of ions in low density plasma is twice - three times as large as corresponding values in cold
gas as a result of increase of electronic Coulomb logarithm. With increase of density the Coulomb
logarithm reduces, and in dense plasma energy losses of ions are close to values, characteristic for
cold substance. In dense plasma at relative small energy below the peak of stopping power the wellknown effect of energy loss decreasing with increase of temperature is substantially moderated by
increase of an effective charge - power losses are dependent weakly on plasma temperature.
Results of calculations are in the reasonable agreement with available experimental data though
as a whole population of values lay a little bit below experimental. The probable reasons of
distinctions and opportunities of improvement of our design procedure are discussed.
The work is supported by the grant RFBR 05-08-01355-а.
References
[1]. Samarskii A.A., Gus`kov S.Yu., Levkovskii A.A. et al., “Investigated in Russia”, 229, 24482459, 2004. http://zhurnal.ape.relarn.ru/articles/2004/229.pdf
[2]. Gus`kov S.Yu., Gubinskaya N. B., Zmitrenko N.V. et al. Rep. on XXXIII Int. (Zvenigorod)
Conf. on Plasma Phys. and ICF, (13 – 17 febr. 2006).
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