Interaction of Fast Particles with Waves in Cosmic Magnetoactive Plasma

Abstract

Until recently, the concepts describing cosmic plasma were very simple (see Alfven & Fiilthammar 1963, Pikel'ner 1965), but it is clear now that they were also more or less naive. Plasma was considered to be a state of matter with a large number of charged particles of both signs (in the cosmos, mostly protons and electrons) interacting with each other and with collective and external electric and magnetic fields. Particle collisions were thought to be responsible for the bremsstrahlung radiation in free-free transitions and, with the radiation, to determine the degree of ionization of the cosmic plasma. The temperature of star surfaces and the interstellar medium was inferred from data on the degree of ionization (Pikel'ner 1965, Kaplan & Pikel'ner 1970). In principle, these con­ cepts are not wrong if the plasma is indeed or in thermodynamic equi­ librium. But is the cosmic plasma in such a condition? Astrophysical observa­ tions in recent years give more and more evidence for violent unstationary processes in the cosmic plasma. We mention only some of the well-known phe­ nomena discovered recently. In very distant regions, quasars, galactic nuclei, the wind from galactic nuclei, supernova explosions, and conditions in the plasma surrounding pulsars all demonstrate nonstationarity. In nearer regions, explosive processes in chromospheric flares, solar bursts of different types, and radar probes of the Sun also indicate great instability. Radar probes show irregularities in the reflected signal even in the quiet Sun time, which indicates the develop­ ment of nonstationary processes in the outer layers. The interplanetary media is confined by the nonstationary solar wind, which creates a bow shock near the Earth and causes many nonstationary phenomena in the magnetosphere. Among them are the substorms. The development of substorms due to the solar wind triggers the release of energy confi ned in the magnetosphere. The plasma near the bowshock is always violent. New observations indicate more and more that the cosmic plasma in many conditions is not in a stationary equilibrium state (Kaplan & Tsytovich 1972a). What about the results of laboratory plasma research? Most experiments on