A5042348021- Solar and Space Plasma Dynamics
- Ionosphere and magnetosphere dynamics
- Astro and Planetary Science
- Geomagnetism and Paleomagnetism Studies
- Magnetic confinement fusion research
- Fluid Dynamics and Turbulent Flows
- Earthquake Detection and Analysis
- Atomic and Subatomic Physics Research
- Plasma Diagnostics and Applications
- Geophysics and Gravity Measurements
- Mass Spectrometry Techniques and Applications
- Economic Growth and Productivity
- Gender, Labor, and Family Dynamics
- Diamond and Carbon-based Materials Research
- Advanced Wireless Communication Techniques
- Advanced MRI Techniques and Applications
University of California, Berkeley
2020-2025
University of Delaware
2017-2022
University of Southampton
2022
Imperial College London
2022
Planetary Science Institute
2022
University of California, Los Angeles
2022
Abstract Parker Solar Probe (PSP), NASA’s latest and closest mission to the Sun, is on a journey investigate fundamental enigmas of inner heliosphere. This paper reports initial observations made by Analyzer for Ions (SPAN-I), one instruments in Wind Electrons Alphas Protons instrument suite. We address presence secondary proton beams concert with ion-scale waves observed FIELDS, electromagnetic fields show two events from PSP’s second orbit that demonstrate signatures consistent...
Turbulent plasmas generate a multitude of thin current structures that can be sites for magnetic reconnection. The Magnetospheric Multiscale (MMS) mission has recently enabled the detailed examination such turbulent in Earth's magnetosheath and revealed novel type reconnection, known as electron-only occur. In ions do not have enough space to couple newly reconnected fields, suppressing ion jet formation resulting thinner sub-proton-scale with faster super-Alfvénic electron jets. this study,...
Abstract The recently discovered electron‐only reconnection has abnormal features like lack of ion outflows and high rates. Using particle‐in‐cell simulations, we investigate their physical mechanisms. rate, when normalized by parameters (), may appear anomalously high, whereas that electron () remains ∼0.1. We propose the essence is insufficient field line bending outside diffusion region, indicating an incomplete development region. It result from bursty in thin current sheets, or small...
We present the Magnetospheric Multiscale (MMS) mission's observations of large-scale reconnection with a laminar ion exhaust containing many electron-scale filamentary current sheets, one which exhibited super-ion-Alfv\'enic electron jet flowing opposite to jet, identified as electron-only reconnection. Despite close proximity (a few inertial lengths) four MMS spacecraft, they recorded different signatures, including differences in magnitude and profile parallel electric fields, dissipation...
We report observations of reconnection exhausts in the Heliospheric Current Sheet (HCS) during Parker Solar Probe Encounters 08 and 07, at 16 Rs 20 , respectively. current sheet accelerated protons to almost twice solar wind speed increased proton core energy by a factor ∼3, due Alfvén being comparable flow these near-Sun distances. Furthermore, were energized super-thermal energies. During E08, found have leaked out exhaust along separatrix field lines, appearing as field-aligned energetic...
During three of its first five orbits around the Sun, Parker Solar Probe (PSP) crossed large-scale heliospheric current sheet (HCS) multiple times and provided unprecedented detailed plasma field observations near-Sun HCS. We report common detections by PSP reconnection exhaust signatures in HCS at heliocentric distances 29.5–107 solar radii during encounters 1, 4, 5. Both sunward antisunward-directed exhausts were observed. In exhausts, detected counterstreaming strahl electrons, indicating...
Reconnection and turbulence are two of the most commonly observed dynamical processes in plasmas, but their relationship is still not fully understood. Using 2.5D kinetic particle-in-cell simulations both strong reconnection, we compare cross-scale transfer energy systems by analyzing generalization von Kármán Howarth equations for Hall magnetohydrodynamics, a formulation that subsumes third-order law steady rates. Even though large scale features quite different, finding decomposition...
Abstract “Electron-only” reconnection, which is both uncoupled from the surrounding ions and much faster than standard arguably ubiquitous in turbulence. One critical step to understanding rate this novel regime model outflow speed that limits transport of magnetic flux, super ion Alfvénic but significantly lower electron Alfvén based on asymptotic reconnecting field. Here we develop a simple determine limiting by taking into account multiscale nature Hall-mediated speed, pressure buildup...
Using kinetic particle-in-cell (PIC) simulations, we simulate reconnection conditions appropriate for the magnetosheath and solar wind, i.e., plasma beta (ratio of gas pressure to magnetic pressure) greater than 1 low shear (strong guide field). Changing simulation domain size, find that ion response varies greatly. For reconnecting regions with scales comparable Larmor radius, ions do not respond dynamics leading ''electron-only'' very large quasi-steady rates. The transition more...
The spectral properties associated with laminar, anti-parallel reconnection are examined using a 2.5D kinetic particle in cell simulation. Both the rate and energy spectrum exhibit three distinct phases: an initiation phase where grows, quasi-steady phase, declining both decrease. During steady exhibits approximately double power law behavior, slope near −5/3 at wave numbers smaller than inverse ion inertial length steeper −8/3 for larger up to electron length. This behavior is consistent...
Observations in Earth's turbulent magnetosheath downstream of a quasiparallel bow shock reveal prevalence electron-scale current sheets favorable for electron-only reconnection where ions are not coupled to the reconnecting magnetic fields. In small-scale turbulence, structures associated with intense limited all dimensions. And since coupling constrained by minimum length scale, dynamics electron is likely be 3D. Here, both 2D and 3D kinetic particle-in-cell simulations used investigate...
Abstract Magnetic reconnection is a fundamental process in space and astrophysical plasmas that converts magnetic energy to particle energy. Recently, novel kind of reconnection, called electron-only has been observed Earth's magnetosheath plasma. A defining characteristic electron jets are but ion absent. This contrast with traditional ion-coupled where both ions electrons exhibit outflowing velocity jets. Findings from the Magnetospheric Multiscale mission observations particle-in-cell...
Abstract We investigate the detailed properties of electron inflow in an electron-only reconnection event observed by four Magnetospheric Multiscale (MMS) spacecraft Earth's turbulent magnetosheath downstream quasi-parallel bow shock. The lack ion coupling was attributed to small-scale sizes current sheets, and bidirectional super-Alfvénic jets indicate that MMS crossed reconnecting sheet on both sides active X-line. Remarkably, presence large asymmetries two inflows, with inflows (normal...
The effect of an external guide field on the turbulence-like properties magnetic reconnection is studied using five different 2.5D kinetic particle-in-cell (PIC) simulations. energy spectrum found to exhibit a slope approximately −5/3 in inertial range, independent field. On contrary, electric range steepens more with and approaches −5/3. In addition, spectral analysis terms generalized Ohm's law performed be consistent PIC simulations turbulence MMS observations. Finally, transfer behavior...
Abstract The quadrupolar out‐of‐plane Hall magnetic field generated during collisionless reconnection propagates away from the x line as a kinetic Alfvén wave (KAW). While it has been shown that this KAW carries substantial Poynting flux and super‐Alfvenically, how damps is not well understood. In study, damping examined using particle‐in‐cell simulations of antiparallel symmetric in one‐dimensional current sheet equilibrium. simulations, vector typical magnitude comparable to an inverse...
We report Magnetospheric Multiscale four-spacecraft observations of a thin reconnecting current sheet with weakly asymmetric inflow conditions and guide field approximately twice the magnetic field. The event was observed at interface interlinked lines flank magnetopause when maximum spacecraft separation 370 km covered ∼1.7 ion inertial lengths (di) in reconnection outflow direction. ion-scale made it possible to observe transition from electron-only super ion-Alfvénic near electron...
Magnetic reconnection has long been thought to play an important role in turbulent plasmas – with the nonlinear dynamics of systems being well known self-consistently generate intense current structures and associated magnetic shears that can be sites where so-called turbulence-driven occur. However, complex three-dimensional topologies small-scale nature these events have traditionally made it challenging assess from either a numerical or observational perspective. Recent...
The recently discovered electron-only reconnection has drawn great interests due to abnormal features like lack of ion outflows and high rates. Using particle-in-cell simulations, we investigate their physical mechanisms. rate, when normalized by parameters ($R_i$), may appear anomalously high, whereas that electron ($R_e$) remains ~0.1. We propose the essence $R_i$ is insufficient field line bending outside diffusion region, indicating an incomplete development region. It result from bursty...
Earth and Space Science Open Archive This work has been accepted for publication in Geophysical Research Letters. Version of RecordESSOAr is a venue early communication or feedback before peer review. Data may be preliminary. Learn more about preprints. preprintOpen AccessYou are viewing the latest version by default [v1]Parker Solar Probe observations solar wind energetic proton beams produced magnetic reconnection near-Sun heliospheric current sheetAuthorsTai-DucPhaniDJ. L.VernieroiDDavin...
The effect of an external guide field on the turbulence-like properties magnetic reconnection is studied using five different 2.5D kinetic particle-in-cell (PIC) simulations. energy spectrum found to exhibit a slope approximately -5/3 in inertial range, independent field. On contrary, electric spectrum, range steepens more with and approaches -5/3. In addition, spectral analysis terms generalized Ohm's law performed be consistent PIC simulations turbulence MMS observations. Finally, transfer...
Gender diversity in the field of heliophysics is severely lacking, to detriment all members field.This status due part insufficient institutional support and inclusion practices for transgender nonbinary people other gender minorities.In this white paper, we describe current state profession through a collective lens trans heliophysicists.We then make recommendations on ways build resources, opportunities, that seek welcome, uplift, retain gender-expansive persons our field.1. We acknowledge...