Modulation of suprathermal electrons and their heat flux in compressive plasma structures in the solar wind

Electrons are a subsonic plasma species in the solar wind. Their kinetic behaviour is - to a much greater extent than the proton behaviour - the result of an interplay between global properties of the heliosphere and local plasma processes. The global properties of the heliosphere include the interplanetary electrostatic potential, the large-scale interplanetary magnetic field, and the density profile of the plasma. The local plasma processes include collisions, wave-particle interactions, and turbulence. Through this interplay, the electron distribution function develops interesting kinetic features that are observable in situ. In addition to a quasi-Maxwellian core, the distribution exhibits suprathermal populations in the form of the strahl and halo components as well as cut-offs due to loss effects in the interplanetary potential.

We discuss the interaction of suprathermal electrons with local structures such as compressive waves and magnetic holes, and the impacts of these structures on the global electron transport in the heliosphere. The regulation of the electron heat flux is of particular interest in this context. We support these results with observations from Solar Orbiter and Parker Solar Probe.