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P: Plasmaphysik
P 21: Poster: Grundprobleme, Theorie, Plasmatechnologie, Astrophysikalische Plasmen
P 21.16: Poster
Montag, 18. März 2002, 17:40–18:40, HZO Foyer
Nonlinear electrostatic structures in the weakly-collisional solar atmosphere — •Claudia-Veronika Meister1 and Alexandra Volosevich2 — 1Space Plasma Physics, Potsdam, Germany — 2State University, Mogilev, Belarus
Basing on recent models of the solar atmosphere, the excitation of collisional ion-acoustic turbulence in the region of the solar temperature minimum with about 4200 K is investigated. At this temperature minimum, both the charged particle densities (ne≈1017−1019 m−3) and the neutral particle densities (ne≈1019−1021 m−3) are rather high. An ion-acoustic instability occurs because of electrical currents or as a consequence of charged particle beams in the plasma with strong heat conductivity. There, the energy of the electron drift motion transferred to the waves is larger than the energy loss caused by the ion viscosity.
Further, within the frame of hydrodynamics, taking into account wave and Joule heating, a nonlinear differential equation is derived, which describes the evolution of nonlinear ion-acoustic waves in a weakly collisional plasma. The differential equation is solved using the improved Krylov-Bogoljubov method [Korn G.A., Korn T.M., Mathematical Handbook, McGraw-Hill Book Company, New York 1968]. Widely analytical results are obtained and estimates of the parameters of possible nonlinear electrostatic structures are found for the case of the solar atmosphere.