A5089632976- Ionosphere and magnetosphere dynamics
- Magnetic confinement fusion research
- Solar and Space Plasma Dynamics
- Electron and X-Ray Spectroscopy Techniques
- Power Line Communications and Noise
- Geophysics and Gravity Measurements
- Magnetic Properties and Applications
- Quantum, superfluid, helium dynamics
- Theoretical and Computational Physics
- Astro and Planetary Science
- Adaptive optics and wavefront sensing
- Astrophysical Phenomena and Observations
- Magnetic Field Sensors Techniques
- Plasma Diagnostics and Applications
- Inertial Sensor and Navigation
- Astrophysics and Star Formation Studies
- Geomagnetism and Paleomagnetism Studies
- Radio Astronomy Observations and Technology
- Semiconductor materials and devices
- Advanced Electron Microscopy Techniques and Applications
- Optical Wireless Communication Technologies
- Gas Dynamics and Kinetic Theory
- GNSS positioning and interference
- Satellite Communication Systems
- Astronomy and Astrophysical Research
University of Wisconsin–Madison
2016-2023
Los Alamos National Laboratory
2019
The spontaneous formation of magnetic islands is observed in driven, antiparallel reconnection on the Terrestrial Reconnection Experiment. We here provide direct experimental evidence that plasmoid instability active at electron scale inside ion diffusion region a low collisional regime. experiments show island occurs smaller system size than predicted by extended magnetohydrodynamics or fully collisionless simulations. This more effective seeding emphasizes their importance to naturally...
Abstract Alfvénic interactions that transfer energy from large to small spatial scales lie at the heart of magnetohydrodynamic turbulence. An important feature turbulence is generation negative residual energy—excess in magnetic fluctuations compared velocity fluctuations. By contrast, an MHD Alfvén wave has equal amounts each type. quasi-modes do not satisfy dispersion relation and exist only presence a nonlinear term can contain either positive or energy, but until now, intuitive physical...
Fully kinetic simulations are applied to the study of 2D anti-parallel reconnection, elucidating dynamics by which electron fluid maintains force balance within both diffusion region (EDR) and ion (IDR). Inside IDR, magnetic field-aligned pressure anisotropy ($p_{e\parallel}\gg p_{e\perp})$ develops upstream EDR. Compared previous investigations, use modern computer facilities allows for at natural proton mass ratio $m_i/m_e=1836$. In this high-$m_i/m_e$-limit changes qualitatively, as...
Magnetic reconnection is explored on the Terrestrial Reconnection Experiment (TREX) for asymmetric inflow conditions and in a configuration where absolute rate of set by an external drive. pileup enhances upstream magnetic field high density inflow, leading to increased Alfven speed helping lower normalized values expected from theoretical consideration. In addition, shock interface between far supersonic plasma region flux observed, important overall force balance system, hereby...
During magnetic reconnection in collisionless space plasma, the electron fluid decouples from field within narrow current layers, and theoretical models for this process can be distinguished terms of their predicted layer widths. From theory, off-diagonal stress pressure tensor is related to thermal non-circular orbit motion electrons around lines. This becomes significant when width reconnecting approaches small characteristic length scale motion. To aid situ spacecraft numerical...
The rate of reconnection characterizes how quickly flux and mass can move into out the region. In Terrestrial Reconnection EXperiment (TREX), at which antiparallel asymmetric occurs is modulated by presence a shock region pileup in high-density inflow. Simulations utilizing generalized Harris-sheet geometry have tentatively shown agreement with TREX's measured scaling relative to system size, indicative transition from ion-coupled toward electron-only reconnection. Here, we present...
Supermagnetosonic perpendicular flows are magnetically driven by a large radius theta-pinch experiment. Fine spatial resolution and macroscopic coverage allow the full structure of plasma-piston coupling to be resolved in laboratory experiment for first time. A moving ambipolar potential is observed reflect unmagnetized ions twice piston speed. Magnetized electrons balance radial via Hall currents generate signature quadrupolar magnetic fields. Electron heating reflected ion foot adiabatic.
Alfv\'enic interactions which transfer energy from large to small spatial scales lie at the heart of magnetohydrodynamic turbulence. An important feature turbulence is generation negative residual -- excess in magnetic fluctuations compared velocity fluctuations. By contrast, an MHD Alfv\'en wave has equal amounts each type. quasimodes that do not satisfy dispersion relation and exist only presence a nonlinear term can contain either positive or energy, but until now intuitive physical...
For most laboratory plasma experiments, Coulomb collisions between the particle species are sufficiently frequent that distribution functions relaxed to a near-Maxwellian form. This hampers applicability of such experiments phenomena observed in tenuous and near-collisionless space plasma. The Terrestrial Reconnection EXperiment (TREX) at Wisconsin Plasma Physics Laboratory aims study collisionless reconnection for parameters relevant Earth's magnetosphere. To reduce role collisional...