http://arxiv.org/abs/2304.03715
Collisionless and weakly collisional plasmas often exhibit non-thermal quasi-equilibria. Among these quasi-equilibria, distributions with power-law tails are ubiquitous. It is shown that the statistical-mechanical approach originally suggested by Lynden-Bell (1967) can easily recover such power-law tails. Moreover, we show that, despite the apparent diversity of Lynden-Bell equilibria, a generic form of the equilibrium distribution at high energies is a
hard' power-law tail $\propto \varepsilon^{-2}$, where $\varepsilon$ is the particle energy. The shape of thecore’ of the distribution, located at low energies, retains some dependence on the initial condition but it is the tail (or `halo’) that contains most of the energy. Thus, a degree of universality exists in collisionless plasmas.
R. Ewart, M. Nastac and A. Schekochihin
Mon, 10 Apr 23
23/36
Comments: 28 pages, 5 figures