Search Publications
Phase diagram for magnetic reconnection in heliophysical, astrophysical, and laboratory plasmas
Ji, Hantao; Daughton, William
Recent progress in understanding the physics of magnetic reconnection is conveniently summarized in terms of a phase diagram which organizes the essential dynamics for a wide variety of applications in heliophysics, laboratory, and astrophysics. The two key dimensionless parameters are the Lundquist number and the macrosopic system size in units o…
A weakened cascade model for turbulence in astrophysical plasmas
Howes, G. G.; Dorland, W.; Tenbarge, J. M.
A refined cascade model for kinetic turbulence in weakly collisional astrophysical plasmas is presented that includes both the transition between weak and strong turbulence and the effect of nonlocal interactions on the nonlinear transfer of energy. The model describes the transition between weak and strong MHD turbulence and the complementary tra…
Linear and nonlinear Landau resonance of kinetic Alfvén waves: Consequences for electron distribution and wave spectrum in the solar wind
Crabtree, C.; Rudakov, L.; Mithaiwala, M. +1 more
Kinetic Alfvén wave turbulence in solar wind is considered and it is shown that non-Maxwellian electron distribution function has a significant effect on the dynamics of solar wind plasmas. Linear Landau damping leads to the formation of a plateau in the parallel electron distribution function which diminishes the Landau damping rate significantly…
Electron dynamics in two-dimensional asymmetric anti-parallel reconnection
Pritchett, P. L.; Egedal, J.; Daughton, W. +1 more
Kinetic simulations and spacecraft observations have documented strong anisotropy in the electron distribution function during magnetic reconnection. The level and role of electron pressure anisotropy is investigated for asymmetric geometries applicable to reconnection in the day-side magnetopause. A previously derived analytic model for the press…
The inversion layer of electric fields and electron phase-space-hole structure during two-dimensional collisionless magnetic reconnection
Lefebvre, Bertrand; Chen, Li-Jen; Torbert, Roy B. +1 more
Based on two-dimensional fully kinetic simulations that resolve the electron diffusion layer in undriven collisionless magnetic reconnection with zero guide field, this paper reports the existence and evolution of an inversion layer of bipolar electric fields, its corresponding phase-space structure (an electron-hole layer), and the implication to…
Chromospheric anemone jets and magnetic reconnection in partially ionized solar atmosphere
Shibata, K.; Isobe, H.; Singh, K. A. P. +1 more
The solar optical telescope onboard Hinode with temporal resolution of less than 5 s and spatial resolution of 150 km has observed the lower solar atmosphere with an unprecedented detail. This has led to many important findings, one of them is the discovery of chromospheric anemone jets in the solar chromosphere. The chromospheric anemone jets are…
Energy budgets in collisionless magnetic reconnection: Ion heating and bulk acceleration
Belmont, G.; Aunai, N.; Smets, R.
This paper investigates the energy transfer in the process of collisionless antiparallel magnetic reconnection. Using two-dimensional hybrid simulations, we measure the increase of the bulk and thermal kinetic energies and compare it to the loss of magnetic energy through a contour surrounding the ion decoupling region. It is shown, for both symme…
Numerical simulations to study solar wind turbulence
Sharma, R. P.; Kumar, Sanjay; Kumar, Sachin +2 more
Numerical simulation of coupled equations of kinetic Alfvén wave (KAW) and ion acoustic wave is presented in the solar wind. The nonlinear dynamical equations satisfy the modified Zakharov system of equations by taking the nonadiabatic response of the background density. The ponderomotive nonlinearity is incorporated in the wave dynamics. The effe…
Plasma diffusion in self-consistent fluctuations
Belmont, G.; Aunai, N.; Smets, R. +1 more
The problem of particle diffusion in position space, as a consequence of electromagnetic fluctuations is addressed. Numerical results obtained with a self-consistent hybrid code are presented, and a method to calculate diffusion coefficient in the direction perpendicular to the mean magnetic field is proposed. The diffusion is estimated for two di…