Presented by: Stanislav Boldyrev, University of Wisconsin, Madison

Abstract: The solar wind is a nearly collisionless plasma expanding from the hot solar corona into the interplanetary space. In situ measurements demonstrate that electrons propagating from the sun, have a complex velocity distribution function. In addition to the nearly Maxwellian thermal core, their distribution function contains a narrow beam of suprathermal electrons streaming along the magnetic field lines extending from the corona. The non-Maxwellian component of the distribution function is important for heat conduction, kinetic plasma instabilities, waves, and turbulence, which govern both the dynamics and thermodynamics of the solar wind. In this talk, I will demonstrate that the electron beam plays a significant role in the heating of solar wind electrons. In particular, it helps to explain why the electron temperature declines with the radial distance much slower than it would be predicted by adiabatic law, which is a fundamental long-standing problem of solar wind heating. I will also discuss an intriguing analogy between the problems of electron heating in the solar wind and in the expander region of a plasma mirror machine.

Host:  Dmitri Uzdensky

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