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Firehose and Mirror Instabilities in a Collisionless Shearing Plasma

Kunz, Matthew W.; Schekochihin, Alexander A.; Stone, James M.

Hybrid-kinetic numerical simulations of firehose and mirror instabilities in a collisionless plasma are performed in which pressure anisotropy is driven as the magnetic field is changed by a persistent linear shear S. For a decreasing field, it is found that mostly oblique firehose fluctuations grow at ion Larmor scales and saturate with energies …

Čerenkov Emission of Quasiparallel Whistlers by Fast Electron Phase-Space Holes during Magnetic Reconnection

Eastwood, J. P.; Andersson, L.; Goldman, M. V. +6 more

Kinetic simulations of magnetotail reconnection have revealed electromagnetic whistlers originating near the exhaust boundary and propagating into the inflow region. The whistler production mechanism is not a linear instability, but rather is Čerenkov emission of almost parallel whistlers from localized moving clumps of charge (finite-size quasipa…

Electron Dynamics in the Diffusion Region of an Asymmetric Magnetic Reconnection

Fazakerley, A. N.; André, M.; Vaivads, A. +2 more

During a magnetopause crossing near the subsolar point Cluster observes the ion diffusion region of antiparallel magnetic reconnection. The reconnecting plasmas are asymmetric, differing in magnetic field strength, density, and temperature. Spatial changes in the electron distributions in the diffusion region are resolved and investigated in detai…

Backward Wave Cyclotron-Maser Emission in the Auroral Magnetosphere

Kellett, B. J.; Vorgul, I.; Bingham, R. +4 more

In this Letter, we present theory and particle-in-cell simulations describing cyclotron radio emission from Earth's auroral region and similar phenomena in other astrophysical environments. In particular, we find that the radiation, generated by a down-going electron horseshoe distribution is due to a backward-wave cyclotron-maser emission process…