A5020490707- Solar and Space Plasma Dynamics
- Ionosphere and magnetosphere dynamics
- Astro and Planetary Science
- Geomagnetism and Paleomagnetism Studies
- Geophysics and Gravity Measurements
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Magnetic confinement fusion research
- Spacecraft and Cryogenic Technologies
- Atmospheric Ozone and Climate
- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Dark Matter and Cosmic Phenomena
- Astronomy and Astrophysical Research
- Solar Radiation and Photovoltaics
- Atomic and Molecular Physics
- Advanced Thermodynamics and Statistical Mechanics
- Space Science and Extraterrestrial Life
- Cosmology and Gravitation Theories
- Earthquake Detection and Analysis
- Planetary Science and Exploration
- Quantum, superfluid, helium dynamics
- History and Developments in Astronomy
- Solar Thermal and Photovoltaic Systems
- Neutrino Physics Research
Boston University
2015-2024
Institute for Advanced Study
2021-2024
Harvard University
2021-2024
Johns Hopkins University Applied Physics Laboratory
2022-2023
EarthTech International (United States)
2022-2023
Harvard University Press
2022-2023
University of Illinois Urbana-Champaign
2023
European Organization for Nuclear Research
2023
King's College London
2023
University of Notre Dame
2023
The recent observations of the anomalous cosmic ray (ACR) energy spectrum as Voyager 1 and 2 crossed heliospheric termination shock have called into question conventional source these energetic particles. We suggest that sectored magnetic field, which results from flapping current sheet, piles up it approaches heliopause, narrowing sheets separate sectors triggering onset collisionless reconnection. Particle-in-cell simulations reveal most is released this goes ions with significant but...
The effects of the highly damped modes in energy and reaction rates a plasma are discussed. These modes, with wave numbers k≫kD, even being only weakly excited, less than kBT per mode, make significant contribution to screening plasma. When de Broglie wavelength is much distance closest approach thermal electrons, classical analysis can be made. It assumed, analysis, ℏ→0, that fluctuations ℏω≪kBT. Using fluctuation-dissipation theorem, spectra ℏ≠0 appreciably decreased. decrease mainly for...
We perform three-dimensional numerical simulations of stellar winds early-M dwarf stars. Our incorporate observationally reconstructed large-scale surface magnetic maps, suggesting that the complexity field can play an important role in angular momentum evolution star, possibly explaining large distribution periods dM stars, as reported recent works. In spite diversity topologies among stars our sample, we find wind flowing near (rotational) equatorial plane carries most momentum, but there...
We numerically model the coronal mass ejection (CME) event of 2003 October 28 that erupted from AR 10486 and propagated to Earth in less than 20 hr, causing severe geomagnetic storms. The magnetohydrodynamic (MHD) is formulated by first arriving at a steady state corona solar wind employing synoptic magnetograms. initiate two CMEs same active region, one approximately day earlier preconditions for much faster CME on 28th. This second travels through rate over 2500 km s−1, driving strong...
We propose that magnetic reconnection at the heliopause (HP) only occurs where interstellar field points nearly anti-parallel to heliospheric field. By using large-scale magnetohydrodynamic (MHD) simulations of heliosphere provide initial conditions for kinetic HP reconnection, we show energetic pickup ions downstream from solar wind termination shock induce large diamagnetic drifts in reconnecting plasma and stabilize non-anti-parallel reconnection. With this constraint, MHD can most likely...
Tau Boo is an intriguing planet-host star that believed to undergo magnetic cycles similar the Sun, but with a duration about one order of magnitude smaller than solar cycle. With use observationally derived surface field maps, we simulate stellar wind by means three-dimensional MHD numerical simulations. As properties depend on particular characteristics field, show varies during observed epochs Although mass loss-rates find (~2.7e-12 Msun/yr) vary less 3 per cent cycle, our angular...
The classic accepted view of the heliosphere is a quiescent, comet-like shape aligned in direction Sun's travel through interstellar medium (ISM) extending for 1000's AUs (AU: astronomical unit). Here we show, based on magnetohydrodynamic (MHD) simulations, that tension (hoop) force twisted magnetic field sun confines solar wind plasma beyond termination shock and drives jets to North South very much like astrophysical jets. These are deflected into tail region by motion Sun ISM similar bent...
Accurate space weather forecasting requires knowledge of the trajectory coronal mass ejections (CMEs), including any deflections close to Sun or through interplanetary space. Kay et al. 2013 introduced ForeCAT, a model CME deflection resulting from background solar magnetic field. For field solution corresponding Carrington Rotation (CR) 2029 (declining phase, April-May 2005), majority CMEs deflected Heliospheric Current Sheet (HCS), minimum in pressure on global scales. Most occurred below...
To predict whether a coronal mass ejection (CME) will impact Earth, the effects of background on CME's trajectory must be taken into account. We develop model, ForeCAT (Forecasting Altered Trajectory), CME deflection due to magnetic forces. includes expansion, three-part propagation and drag deflection. Given solar wind conditions, launch site CME, properties (mass, final speed, initial radius, strength), predicts CME. Two different backgrounds are considered: scaled based type II radio...
We present a three‐dimensional (3‐D) numerical ideal magnetohydrodynamics (MHD) model, describing the time‐dependent expulsion of plasma and magnetic flux from solar corona that resembles coronal mass ejection (CME). begin by developing global steady‐state model wind gives reasonable description conditions near minimum. The field possesses high‐latitude holes closed lines at low latitudes in form helmet streamer belt with current sheet equator. further reproduce fast slow speed high...
We show that an interstellar magnetic field can produce a north-south asymmetry in the solar wind termination shock. Using Voyager 1 and 2 measurements, we suggest angle α between velocity is 30° < 60°. The distortion of shock such particles could have streamed outward along spiral interplanetary connecting to when spacecraft was within ~2 AU larger southern hemisphere, be connected it ~5 shock, but with from streaming inward field. Tighter constraints on should possible crosses next several years.
All current global models of the heliosphere are based on assumption that magnetic field in heliosheath, region close to heliopause (HP), is laminar. We argue heliospheric not laminar but instead consists bubbles. refer it as bubble-dominated heliosheath region. Recently, we proposed annihilation "sectored" within compressed its approach HP produces anomalous cosmic rays and also energetic electrons. As a product sectored field, densely packed islands (which further interact form bubbles)...
Solar coronal mass ejections (CMEs) produce adverse space weather effects at Earth. Planets in the close habitable zone of magnetically active M dwarfs may experience more extreme than Earth, including frequent CME impacts leading to atmospheric erosion and leaving surface exposed flare activity. Similar occur for hot Jupiters with orbits around solar-like stars. We have developed a model, Forecasting CME's Altered Trajectory (ForeCAT), which predicts deflection. adapt ForeCAT simulate...
During the course of its evolution, our Sun and protective magnetic bubble have plowed through dramatically different interstellar environments throughout galaxy. The vast range conditions plasma, gas, dust high-energy cosmic rays on this "solar journey" helped shape solar system that we live in. Today, bubble, or Heliosphere, is likely about to enter a completely new regime space will, yet again, change entire heliospheric interaction how it shields us from environment. Interstellar Probe...
The orientation of the local interstellar magnetic field introduces asymmetries in heliosphere that affect location heliospheric radio emissions and streaming direction ions from termination shock solar wind. We combine observations energetic particle with extensive 3D MHD computer simulations draping over heliopause to show plane is ~ 60-90 degrees galactic plane. This suggests Local Interstellar Cloud differs a larger scale thought parallel
We discuss a model of cosmic ray acceleration that accounts for the observations anomalous rays (ACRs) by Voyager 1 and 2. The appeals to fast magnetic reconnection rather than shocks as driver acceleration. ultimate source energy is associated with field reversals occur in heliosheath. It expected will throughout heliosheath, but especially near heliopause where flows slow down diverge respect interstellar wind also boundary sector heliospheric current sheet. While first-order Fermi theory...
The rapid rotation (P=0.44 d) of the M dwarf V374Peg (M4) along with its intense magnetic field point toward magneto-centrifugal acceleration a coronal wind. In this work, we investigate structure wind by means 3D magnetohydrodynamical (MHD) numerical simulations. For first time, an observationally derived surface map is implemented in MHD models stellar winds for low mass star. We show that deviates greatly from low-velocity, low-mass-loss rate solar-type find general scaling relations...