Modification of a magnetic field by plasma mechanisms

The review is devoted to the question of the rapid modification (generation, damping, etc.) of a magnetic field in a collision-dominated plasma, when the frequency $\gamma$ of the process is lower than the electroncollision frequency $v$. The universally employed approach–the dynamo theory–is discussed in Chap. 2. The simplest motions that lead to generation, to rapid annihilation of the “antidynamo”, and to a modification of the topological-pumping type are indicated. The discussion concerns problems of the turbulent dynamos (where a functional approach is used) and of the nonlinear dynamo. In the latter case, the Gibbs ensemble is used; a reverse cascade of magnetic and kinetic energy into the region of small wave numbers is observed. Other plasma mechanisms are discussed, namely the modification of the field by ion sound, the weakly-ionized plasma, and the solid-state plasma (dynamo based on thermal effects)–Chap. 3. It is shown that the modification can be quite effective. Discussed in Chap. 4 are high-frequency oscillations (whistlers, Langmuir oscillations) and their role in the modification of the field. The indicated mechanisms can be effective under conditions of the solar chromosphere.