3 research outputs found
Fourier-Hermite decomposition of the collisional Vlasov-Maxwell system: Implications for the velocity-space cascade
Turbulence at kinetic scales is an unresolved and ubiquitous phenomenon that characterizes both space and laboratory plasmas. Recently, new theories, {\it in-situ} spacecraft observations and numerical simulations suggest a novel scenario for turbulence, characterized by a so-called phase space cascade -- the formation of fine structures, both in physical and velocity space. This new concept is here extended by directly taking into account the role of inter-particle collisions, modeled through the nonlinear Landau operator or the simplified Dougherty operator. The characteristic times, associated with inter-particle correlations, are derived in the above cases. The implications of introducing collisions on the phase space cascade are finally discussed
ViDA: a VlasovDArwin solver for plasma physics at electron scales
We present a VlasovâDArwin numerical code (ViDA) specifically designed to
address plasma physics problems, where small-scale high accuracy is requested
even during the nonlinear regime to guarantee a clean description of the plasma
dynamics at fine spatial scales. The algorithm provides a low-noise description of
proton and electron kinetic dynamics, by splitting in time the multi-advection Vlasov
equation in phase space. Maxwell equations for the electric and magnetic fields are
reorganized according to the Darwin approximation to remove light waves. Several
numerical tests show that ViDA successfully reproduces the propagation of linear and
nonlinear waves and captures the physics of magnetic reconnection. We also discuss
preliminary tests of the parallelization algorithm efficiency, performed at CINECA
on the Marconi-KNL cluster. ViDA will allow the running of Eulerian simulations
of a non-relativistic fully kinetic collisionless plasma and it is expected to provide
relevant insights into important problems of plasma astrophysics such as, for instance,
the development of the turbulent cascade at electron scales and the structure and
dynamics of electron-scale magnetic reconnection, such as the electron diffusion
region
Firefly: The Case for a Holistic Understanding of the Global Structure and Dynamics of the Sun and the Heliosphere
This white paper is on the HMCS Firefly mission concept study. Firefly focuses on the global structure and dynamics of the Sun's interior, the generation of solar magnetic fields, the deciphering of the solar cycle, the conditions leading to the explosive activity, and the structure and dynamics of the corona as it drives the heliosphere