Saint Petersburg State University
15 May 2015, Friday, 13:00
Cavid Erginsoy Seminar Room, Physics Department, 3rd floor
Abstract: In order to predict the main scenarios for control of the electron distribution function (EDF), it is necessary to develop a kind of roadmap of formation of different modes of the EDF in the inhomogeneous unsteady plasmas. The analysis shows that the time scales are determined by the ratio between the transient time (the characteristic time of electron transport through the plasma volume ) and the relaxation times of the EDF momentum (on velocity direction) and energy . Accordingly, it is the ratio between the characteristic size of the plasma and an electron mean free path (momentum relaxation) and a length of the electron energy relaxation. A significant difference between the scale of momentum relaxation and energy , (reaching two or more orders of magnitude) allows to predict the possible modes of the EDF formation, with various degrees of selectivity effects on different groups of electrons, varying between a local EDF when it is possible to affect only the entire ensemble of electrons, and the nonlocal EDF, when different groups of electrons behave independently of each other, so that it is possible to effect on the interest groups of electrons only.