Fokker-Planck equation for energetic particles. The $\kappa$-distribution function

by Claudia Negulescu (UPS/IMT)

Tuesday Jan 7, 2025, 11:15 AM → 12:15 PM Europe/Paris

Amphi Schwartz (IMT)

The main concern of the present talk is the mathematical and numerical
study of a specific Fokker-Planck equation describing the dynamics of
energetic particles (runaway electrons or alpha-particles in a plasma gas) leading in the
long-time limit to a non-equilibrium distribution in the velocity
variable. In particular $\kappa$-distribution functions are the
steady-states of the here considered Fokker-Planck equation and we are
interested in the convergence rate towards these stationary solutions,
as well as in the design of an efficient spectral scheme, permitting
to cope with this long-time asymptotics, without too much numerical
costs. Hermite-spectral schemes are not any more adapted.

Non-equilibrium distributions need to be considered precisely
enough in fusion or astrophysical plasmas in order to accurately
reproduce the fusion plasma dynamics and to understand the impact of
the runaways/alpha-particles on the whole plasma behaviour as well as for issues like
astonaut safety in astrophysics.