Dust Acoustic and Dust Ion Acoustic Nonlinear Structures: Theory and Experiments

S.I. Popel

Institute for Dynamics of Geospheres RAS, Leninsky pr. 38, Building 6, 119334 Moscow, Russia

A review on dust acoustic and dust ion acoustic nonlinear structures in complex (dusty) plasmas is presented. We describe the basic experiments on nonlinear structures in complex plasmas and give the corresponding theoretical description. For the description of formation and evolution of non-stationary dust ion acoustic shocks we have forwarded the so-called ionization source model [1]. This model allows us to describe all the features of the laboratory experiments on dust ion-acoustic shocks [2,3]: the suppression by dust of charge separation in the front of shock; the width of the shock front; the dependence of the shock speed on dust density; the fact [3] that shocks are excited for rather large dust densities. We invstigate the dissipative processes responsible for generation of dust ion acoustic shocks: anomalous dissipation due to dust charging process; absorption and scattering of ions by dust grains; Landau damping. We discuss the possibility of observation of shocks related to the dust charging process in active rocket experiments, which involve the release of some gaseous substance in near-Earth space. As an example of dust ion acoustic shocks in nature, we consider the bow shock formed in the interaction of Solar wind with cometary dusty coma. We present a theory of dust acoustic shocks and give an explanation of the experiments [4] on excitation of two-hump dust acoustic shocks in glow discharge plasma and of the experiments [5] in rf plasma discharge where phase transition was occurred during dust acoustic shock propagation. Furthermore, we investigate the possibility of experimental observation of the dust ion-acoustic solitons in complex plasmas. We show [6] that in complex plasmas important role in the formation of the compressive solitons belongs to the so-called adiabatically trapped electrons. We discuss the possibility of formation of the shock wave-like structures during the soliton evolution.

References

[1] S.I. Popel, A.P. Golub', T.V. Losseva, JETP Letters, 74 (2001) 362; S.I. Popel, A.P. Golub', T.V. Losseva, R. Bingham, and S. Benkadda, Phys. Plasmas, 8 (2001) 1497.
[2] Y. Nakamura, H. Bailung, and P.K. Shukla, Phys. Rev. Lett., 83 (1999) 1602.
[3] Q.-Z. Luo, N. D Angelo, and R. Merlino, Phys. Plasmas, 6 (1999) 3455.
[4] V.E. Fortov, V.I. Molotkov, O.F. Petrov, et al., 29th EPS Conf. on Plasma Phys. and Controlled Fusion, ECA, 26B (2002) O-5.33.
[5] D. Samsonov, private communication (2003).
[6] S.I. Popel, A.P. Golub', T.V. Losseva, et al., Phys. Rev. E, 67 (2003) 056402.


This study is sponsored in part by INTAS (grant no. 01-0391) and RFBR (grants nos. 03-02-16664 and 03-05-64813).