Speaker
Loukas Vlahos
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/I2.J301.pdf
Particle heating and acceleration inside the turbulent Solar Corona
Loukas Vlahos
Department of Physics,
Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
The links between turbulence, reconnection and shocks in unstable plasmas will be discussed
briefly. All three processes co-exist in explosively unstable plasmas, forming a new electromag-
netic environment which we will call here turbulent reconnection, where spontaneous forma-
tion of current sheets inside turbulence appear. The heating and the acceleration of particles will
be the result of the synergy of the stochastic (second order Fermi) and the systematic acceler-
ation (first order Fermi). The solar atmosphere is magnetically coupled with a turbulent driver
(the convection zone) therefore the formation of turbulent reconnection in the solar atmosphere
is externally driven. The magnetic topologies observed in the solar atmosphere are generated
and driven by the convective motions bellow the solar surface and leading to spontaneous gen-
eration of reconnecting current sheets and small and large scale eruptions which reinforce the
turbulent reconnection state. It is shown that long term heating and impulsive heating of the
plasma up to 10’s of million degrees and generation of Solar Energetic Particles is a natural
consequence of the turbulent state of the solar atmosphere. The observed small or large scale
eruptions are the signatures of the turbulent solar atmosphere. For the purpose of this review
we can split the solar atmosphere in two broad classes of magnetic topologies (1) the quiet sun,
where the magnetic field is weak and chaotic and (2) the active regions, where the magnetic
fields are stronger and complex but we can have a rough estimate of their topology from the
Non-Linear Force Free Extrapolations. The large eruptions which are related with large scale
magnetic reconstructions (Flares, Coronal Mass Ejection) appear in active regions were heat-
ing (stochastic) and particle acceleration (systematic) of the high energy tail of the distribution
function co-exist almost in equal footing. In the quite sun or the active regions during the non-
eruptive phase, the small scale explosions (microflares, nanoflares) dominate and the stochastic
heating overpower particle acceleration. Turbulent reconnection, once it is established in the so-
lar corona, drives corona heating and particle acceleration in all explosions in the solar surface
from nanoflares to CMEs.
