A5021166733- Solar and Space Plasma Dynamics
- Ionosphere and magnetosphere dynamics
- Magnetic confinement fusion research
- Geomagnetism and Paleomagnetism Studies
- Plasma Diagnostics and Applications
- Particle accelerators and beam dynamics
- Magnetic Field Sensors Techniques
- Nuclear Physics and Applications
- Astro and Planetary Science
- Characterization and Applications of Magnetic Nanoparticles
- Astrophysics and Star Formation Studies
- Physics of Superconductivity and Magnetism
- Nuclear reactor physics and engineering
- Ion-surface interactions and analysis
- Magnetic Properties and Applications
- Magnetic properties of thin films
- Cold Fusion and Nuclear Reactions
- Copper Interconnects and Reliability
- Underwater Acoustics Research
- Geophysical and Geoelectrical Methods
- Dust and Plasma Wave Phenomena
- Gyrotron and Vacuum Electronics Research
- Silicon Carbide Semiconductor Technologies
- Electromagnetic Compatibility and Noise Suppression
- Gamma-ray bursts and supernovae
Dartmouth College
2025
Massachusetts Institute of Technology
2019-2023
Fusion Academy
2019-2023
Fusion (United States)
2019-2023
Institute for Advanced Study
2023
Plasma Technology (United States)
2019-2023
Princeton University
2023
Zhejiang University
2016
Atmospheric ion escape plays a crucial role in the evolution of planetary climate and habitability. While Mars has been focus extensive in-situ spacecraft observations, our understanding at constrained by single-point measurements, which fail to distinguish spatial temporal variability. Observations from NASA's Atmosphere Volatile EvolutioN (MAVEN) mission China's Tianwen-1 provide complementary observations Martian space environment unique opportunity study variability escape. Here, we...
Abstract We report on a first-principles numerical and theoretical study of plasma dynamo in fully kinetic framework. By applying an external mechanical force to initially unmagnetized plasma, we develop self-consistent treatment the generation “seed” magnetic fields, formation turbulence, inductive amplification fields by fluctuation dynamo. Driven large-scale motions unmagnetized, weakly collisional are subject strong phase mixing, which leads development thermal pressure anisotropy. This...
SignificanceAstronomical observations indicate that dynamically important magnetic fields are ubiquitous in the Universe, while their origin remains a profound mystery. This work provides paradigm for understanding of cosmic magnetism by taking into account effects microphysics collisionless plasmas on macroscopic astrophysical processes. We demonstrate first can be spontaneously generated Universe generic motions turbulence through kinetic plasma physics, and thereby ubiquitously...
We report analytical and numerical investigations of subion-scale turbulence in low-beta plasmas using a rigorous reduced kinetic model. show that efficient electron heating occurs is primarily due to Landau damping Alfvén waves, as opposed Ohmic dissipation. This collisionless facilitated by the local weakening advective nonlinearities ensuing unimpeded phase mixing near intermittent current sheets, where free energy concentrates. The linearly damped electromagnetic fluctuations at each...
We derive, and validate numerically, an analytical model for electron-only magnetic reconnection applicable to strongly magnetized plasmas. Our predicts subion-scale rates significantly higher than those pertaining large-scale reconnection, aligning with recent observations simulations. apply this the problem of inverse energy transfer at subion scales. derive time-dependent scaling laws decay typical structure dimensions that differ from previously found in magnetohydrodynamics regime....
This paper proposes a novel, reconnection-based, solvable analytical model for the inverse transfer of magnetic energy, longstanding problem with far reaching implications in galactic magnetogenesis and high-energy emission gamma-ray bursts.
It has been recently shown numerically that there exists an inverse transfer of magnetic energy in decaying, nonhelical, magnetically dominated, magnetohydrodynamic turbulence 3-dimensions (3D). We suggest reconnection is the underlying physical mechanism responsible for this transfer. In two-dimensional (2D) case, easily inferred to be due smaller islands merging form larger ones via reconnection. find scaling behaviour similar between 2D and 3D cases, i.e., evolves as $t^{-1}$, power...
ABSTRACT We investigate the spectral properties of electromagnetic fluctuations sub-ion scale turbulence in weakly collisional, low-beta plasmas using a two-field isothermal gyrofluid model. The numerical results strongly support description as critically balanced Kolmogorov-like cascade kinetic Alfvén wave fluctuations, amended by previous studies to include intermittency effects. measured universal index energy spectra from systems with different flux-unfreezing mechanisms excludes role...
Magnetic reconnection and plasma turbulence are ubiquitous processes important for laboratory, space, astrophysical plasmas. Reconnection has been suggested to play an role in the energetics dynamics of by observations, simulations, theory two decades. The fundamental properties at kinetic scales, essential understanding general problem magnetized turbulence, remain largely unknown present. Here, we present application magnetic flux transport method that can accurately identify a...
The physical picture of interacting magnetic islands provides a useful paradigm for certain plasma dynamics in variety environments, such as the solar corona, heliosheath, and Earth's magnetosphere. In this work, we derive an island kinetic equation to describe evolution distribution function (in area flux islands) subject collisional integral designed account role reconnection during mergers. This is used study inverse transfer energy through coalescence 2D. We solve our numerically three...
Saturation of Alfvén modes driven unstable by a distribution high energy particles as function collisionality is investigated with guiding center code, using numerical eigenfunctions produced linear theory and particle distributions. The most important resonance found it shown that when the domain bounded, not allowing to collisionlessly escape, saturation amplitude given balance mixing time for nearby collisionally diffuse across width. amplitudes are in agreement theoretical predictions...
We report on an analytical and numerical study of the dynamics a three-dimensional array identical magnetic flux tubes in reduced-magnetohydrodynamic description plasma. propose that long-time evolution this system is dictated by flux-tube mergers such are dynamically constrained conservation pertinent (ideal) invariants, {\it viz.} potential axial fluxes each tube. also direction perpendicular to merging plane, evolve critically-balanced fashion. These notions allow us construct model for...
This article is the first design study of a combined interferometer and polarimeter on compact, high-field, high-density, net-energy tokamak. Recent advances in superconducting technology have made possible designs for high magnetic field fusion power plants, such as ARC [Sorbom et al., Fusion Eng. Des. 100, 378 (2015)], experiments, SPARC [Greenwald PSFC Report No. RR-18-2 (2018)]. These new create both challenges opportunities plasma diagnostics. The diagnostic proposed this work, called...
We derive, and validate numerically, an analytical model for electron-only magnetic reconnection applicable to strongly magnetized (low-beta) plasmas. Our predicts sub-ion-scale rates significantly higher than those pertaining large-scale reconnection, aligning with recent observations simulations. apply this the problem of inverse magnetic-energy transfer at sub-ion scales. derive time-dependent scaling laws energy decay typical structure dimensions that differ from previously found in MHD...
Magnetic reconnection and plasma turbulence are ubiquitous processes important for laboratory, space, astrophysical plasmas. Reconnection has been suggested to play an role in the energetics dynamics of by observations, simulations, theory two decades. The fundamental properties at kinetic scales, essential understanding general problem magnetized turbulence, remain largely unknown present. Here, we present application magnetic flux transport method that can accurately identify a...
The parallel current driven by applied helicon waves is evaluated in tokamak geometry along with the radio frequency (rf) power absorbed passing electrons. results are compared corresponding expressions for lower hybrid drive. efficiency of both drive schemes found to be same any single wave frequency, mode number limit. evaluation currents performed using an adjoint technique. Tokamak retained eigenfunction expansion appropriate a transit averaged long mean free path treatment electrons...
We report on a first-principles numerical and theoretical study of plasma dynamo in fully kinetic framework. By applying an external mechanical force to initially unmagnetized plasma, we develop self-consistent treatment the generation ``seed'' magnetic fields, formation turbulence, inductive amplification fields by fluctuation dynamo. Driven large-scale motions unmagnetized, weakly collisional are subject strong phase mixing, which leads development thermal pressure anisotropy. This...
We report analytical and numerical investigations of sub-ion-scale turbulence in low-beta plasmas, focusing on the spectral properties fluctuations electron heating. In isothermal limit, results strongly support a description as critically-balanced Kolmogorov-like cascade kinetic Alfv\'en wave fluctuations, amended by Boldyrev & Perez (Astrophys. J. Lett. 758, L44 (2012)) to include intermittent effects. When constraint isothermality is removed (i.e., with inclusion physics), energy spectrum...
We study in a fully kinetic framework the generation of seed magnetic fields through Weibel instability driven an initially unmagnetized plasma by large-scale shear force. develop analytical model that describes development thermal pressure anisotropy via phase mixing, ensuing exponential growth linear stage, and its saturation when become strong enough to instigate gyromotion particles thereby inhibit their free-streaming. The predicted scaling dependencies saturated on key parameters...