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Particle Acceleration in Stratified 2D MRI Turbulence: From Reconnection to First- and Second-Order Fermi and Shear Acceleration
Astor Sandoval, Mario Riquelme, Jorge Cuadra
Low-luminosity accretion disks around black holes are weakly collisional, potentially enabling nonthermal particle acceleration. Local two-dimensional particle-in-cell simulations…
Secondary Whistler and Ion-cyclotron Instabilities driven by Mirror Modes in Galaxy Clusters
Francisco Ley, Ellen G. Zweibel, Drake Miller +1
Electron cyclotron waves (whistlers), are commonly observed in plasmas near Earth and the solar wind. In the presence of nonlinear mirror modes, bursts of whistlers, usually called…
Particle-in-cell Simulations of the Magnetorotational Instability in Stratified Shearing Boxes
Astor Sandoval, Mario Riquelme, Anatoly Spitkovsky +1
The magnetorotational instability (MRI) plays a crucial role in regulating the accretion efficiency in astrophysical accretion disks. In low-luminosity disks around black holes, su…
Electron Re-acceleration via Ion Cyclotron Waves in the Intracluster Medium
Aaron Tran, Lorenzo Sironi, Francisco Ley +2
In galaxy clusters, the intracluster medium (ICM) is expected to host a diffuse, long-lived, and invisible population of "fossil" cosmic-ray electrons (CRe) with 1-100 MeV energies…
A Heating Mechanism via Magnetic Pumping in the Intracluster Medium
Francisco Ley, Ellen G. Zweibel, Mario Riquelme +3
Turbulence driven by AGN activity, cluster mergers and galaxy motion constitutes an attractive energy source for heating the intracluster medium (ICM). How this energy dissipates i…
Stochastic Ion Acceleration by the Ion-cyclotron Instability in a Growing Magnetic Field
Francisco Ley, Mario Riquelme, Lorenzo Sironi +2
Using 1D and 2D particle-in-cell (PIC) simulations of a plasma with a growing magnetic field , we show that ions can be stochastically accelerated by the ion-cyclotron (IC…
Stochastic Electron Acceleration by the Whistler Instability in a Growing Magnetic Field
Mario Riquelme, Alvaro Osorio, Eliot Quataert
We use 2D particle-in-cell (PIC) simulations to study the effect of the saturated whistler instability on the viscous heating and nonthermal acceleration of electrons in a shearing…
PIC Simulations of Velocity-Space Instabilities in a Decreasing Magnetic Field: Viscosity and Thermal Conduction
Mario Riquelme, Eliot Quataert, Daniel Verscharen
We use particle-in-cell (PIC) simulations of a collisionless, electron-ion plasma with a decreasing background magnetic field, , to study the effect of velocity-space instabilit…
The microphysics of collisionless shock waves
A. Marcowith, A. Bret, A. Bykov +12
Collisionless shocks, that is shocks mediated by electromagnetic processes, are customary in space physics and in astrophysics. They are to be found in a great variety of objects a…
PIC Simulations of Continuously Driven Mirror and Ion Cyclotron Instabilities in High Beta Astrophysical and Heliospheric Plasmas
Mario Riquelme, Eliot Quataert, Daniel Verscharen
We use particle-in-cell (PIC) simulations to study the nonlinear evolution of ion velocity space instabilities in an idealized problem in which a background velocity shear continuo…
Local 2D Particle-in-cell simulations of the collisionless MRI
Mario A. Riquelme, Eliot Quataert, Prateek Sharma +1
The magnetorotational instability (MRI) is a crucial mechanism of angular momentum transport in a variety of astrophysical accretion disks. In systems accreting at well below the E…
Electron Injection by Whistler Waves in Non-relativistic Shocks
Mario A. Riquelme, Anatoly Spitkovsky
Electron acceleration to non-thermal, ultra-relativistic energies (~ 10-100 TeV) is revealed by radio and X-ray observations of shocks in young supernova remnants (SNRs). The diffu…
Magnetic Amplification by Magnetized Cosmic Rays in SNR Shocks
Mario A. Riquelme, Anatoly Spitkovsky
(Abridged) X-ray observations of synchrotron rims in supernova remnant (SNR) shocks show evidence of strong magnetic field amplification (a factor of ~100 between the upstream and…