A universal mirror wave-mode threshold condition for non-thermal space plasma environments

Abstract

Abstract. Magnetic fluctuations are recognized in a large variety of space plasmas by increasingly high resolution, in situ observations as mirror wave mode structures. A typical requirement for the excitation of mirror modes is a dominant perpendicular pressure in a high-beta plasma environment. Contrary, we demonstrate from a realistic kinetic analysis how details of the velocity space distributions are of considerable significance for the instability threshold. Introducing the most common characteristics of observed ion and electron distributions by a mixed suprathermal-loss-cone, we derive a universal mirror instability criterion from an energy principle for collisionless plasmas. As a result, the transition from two temperature Maxwellians to realistic non-thermal features provides a strong source for the generation of mirror wave mode activity, reducing drastically the instability threshold. In particular, a number of space-related examples illuminate how the specific structure of the velocity space distribution dominates as a regulating excitation mechanism over the effects related to changes in the plasma parameters.

Electron Cyclotron Harmonic Wave Instability by Loss Cone Distribution

“…Finally, our new approach of modeling loss cone distribution with well‐defined width and depth provides a potentially wide range applicability in any mirror configuration of plasma, for example, the terrestrial magnetosphere (Summers & Thorne, ) and Jupiter's moon Ganymede (Williams & Mauk, ). In addition to ECH wave instability, the usage of the new loss cone can deal with other instabilities (such as mirror mode; Leubner & Schupfer, ), which is left as future work.…”

On the generation of envelope solitons in the presence of excess superthermal electrons and positrons

“…In recent years the theory of excess superthermal particles has undergone substantial development (Formisano et al 1973;Mendis and Rosenberg 1994;Scudder et al 1981;Marsch et al 1982;Lazar et al 2008;Leubner and Schupfer 2002;Hellberg and Mace 2002;Abbasi and Pajouh 2007;Saini and Kourakis 2008; P.K. Shukla School of Physics, Faculty of Science & Agriculture, University of Kwazulu-Natal, Durban 4000, South Africa Sultana et al 2010;Tribeche and Boubakour 2009;Chuang and Haul 2009;Gill et al 2010).…”

“…Therefore, it is expected that the such environment has excess superthermal (high-energy) charged particles, i.e., electrons and positrons, and therefore they can be described by kappa distribution. Based on the latter, many authors have been studied the effect of superthermal particles (electrons and ions) on different types of linear and nonlinear collective processes in plasmas see example (Leubner and Schupfer 2002;Hellberg and Mace 2002;Abbasi and Pajouh 2007;Saini and Kourakis 2008;Sultana et al 2010;Tribeche and Boubakour 2009;Chuang and Haul 2009;Gill et al 2010).…”

The characteristics of ion acoustic shock waves in non-Maxwellian plasmas with (G′/G)-expansion method

“…Also, effects the spectral index κ and magnetic filed on the solitary structure characteristics is investigated. In addition to above references many authors have been studied the effect of superthermal particles (electrons and ions) on different types of linear and nonlinear collective processes in plasmas (Leubner and Schupfer 2002;Leubner 2004;Abbasi and Pajouh 2007;Saini and Kourakis 2008;Tribeche and Boubakour 2009), but there is not much investigation on propagation waves in three-component plasmas in which electrons and positrons are superthermal. In the special plasmas such as pulsar relativistic wind, interstellar medium and magnetospheres possess the superthermal (non-Maxwellian) high energy electrons and positrons.…”