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Decoding the selfgenerated wave fluctuations and their role in the formation of the solar wind.

This project aims to clarify one challenging aspect in the process of formation of the solar wind, namely, the truly remarkable equipartition and the closely related minimum-energy conditions for the magnetic field energy and the kinetic energy of plasma particles, which is not fully understood nor explained theoretically or numerically. At high kinetic energies (large-beta plasma regime), confinement of the solar wind plasma to small temperature anisotropies is nicely explained by the selfgenerated fluctuations, but there is still no explanation for small kinetic energies (small-beta plasma). To complete this puzzle we have to identify the wave instability constraints (if exist) for both the electron and proton anisotropies under low-beta (< 1) plasma conditions. Space plasmas are collisionpoor and kinetic effects prevail leading to wave fluctuations, which transfer the energy to small scales: wave-particle interactions replace collisions and enhance dispersive effects heating particles and producing suprathermal populations. The existing kinetic approaches of relaxation and selfgeneration in a large-beta plasma (> 1) regime, have to be extended to low beta (< 1) populations, and confronted with typical MHD models, which cannot account for thermal/suprathermal spread and wave-particle interactions. It is expected to provide a valuable feedback for the ongoing ESA/NASA space missions prepared to enter into the Sun's corona and test the first time these low beta plasma models.

Date:1 Oct 2012  →  30 Sep 2013
Keywords:Fluctuations, Solar wind, Selfgenerated wave, Decoding
Disciplines:Astronomy and space sciences