A5053734685- Solar and Space Plasma Dynamics
- Stellar, planetary, and galactic studies
- Ionosphere and magnetosphere dynamics
- Astro and Planetary Science
- Gamma-ray bursts and supernovae
- Radio Astronomy Observations and Technology
- Geophysics and Gravity Measurements
- Astronomy and Astrophysical Research
- Geomagnetism and Paleomagnetism Studies
- Spacecraft Design and Technology
- Astrophysics and Cosmic Phenomena
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Pulsars and Gravitational Waves Research
- Solar Radiation and Photovoltaics
- History and Developments in Astronomy
- Atmospheric Ozone and Climate
- GNSS positioning and interference
- Adaptive optics and wavefront sensing
- Satellite Communication Systems
- Planetary Science and Exploration
- Space Satellite Systems and Control
- Particle Accelerators and Free-Electron Lasers
- Dark Matter and Cosmic Phenomena
- Spacecraft and Cryogenic Technologies
National Radio Astronomy Observatory
2014-2024
New Jersey Institute of Technology
2023
United States Air Force Research Laboratory
2023
Berkeley College
2023
University of California, Berkeley
2023
Marshall Space Flight Center
2023
University of Colorado Boulder
1983-2008
U.S. National Science Foundation
2007
Laboratoire d’études spatiales et d’instrumentation en astrophysique
2002
Laboratoire de Physique des Plasmas
2002
▪ Abstract Radio emission from solar flares offers a number of unique diagnostic tools to address long-standing questions about energy release, plasma heating, particle acceleration, and transport in magnetized plasmas. At millimeter centimeter wavelengths, incoherent gyrosynchrotron electrons with energies tens kilo electron volts several mega plays dominant role. These carry significant fraction the released during impulsive phase flares. decimeter meter coherent radiation can play...
Solar flares--the most powerful explosions in the solar system--are also efficient particle accelerators, capable of energizing a large number charged particles to relativistic speeds. A termination shock is often invoked standard model flares as possible driver for acceleration, yet its existence and role have remained controversial. We present observations flare trace morphology dynamics using high-cadence radio imaging spectroscopy. show that disruption coincides with an abrupt reduction...
ABSTRACT We present new radio continuum images and a source catalogue from the MeerKAT survey in direction of Small Magellanic Cloud. The observations, at central frequency 1.3 GHz across bandwidth 0.8 GHz, encompass field view ∼7° × 7° result with resolution 8 arcsec. median broad-band Stokes I image Root Mean Squared noise value is ∼11 μJy beam−1. produced these contains 108 330 point sources 517 compact extended sources. also describe UHF (544–1088 MHz) single pointing observation. report...
We observed the fast coronal mass ejection (CME) of 1998 April 20 with radioheliograph at Nançay, France, between 164 and 432 MHz. Spectroscopic data were obtained 40 800 MHz by spectrometer Tremsdorf, Germany, kHz 14 WAVES instrument on board Wind spacecraft. Energetic particle from 3D Plasma Particle experiment. The CME was in white light Large-Angle Spectrometric COronagraph experiment Solar Heliospheric Observatory For first time, expanding loops are imaged directly radio wavelengths....
All magnetized planets in the solar system emit intense cyclotron maser radiation. Like Jupiter, extrasolar giant are probably magnetized. If, addition, there is a source of energetic (keV) electrons their magnetospheres, from auroral processes or as result magnetic coupling between planet and satellite, it likely that cyclotron-maser emitters. Detection follow-up observations radiation an exoplanet would reveal presence, strength, complexity planetary field, planet's rotation rate, possibly...
view Abstract Citations (124) References (56) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Angular Scattering of Solar Radio Emission by Coronal Turbulence Bastian, T. S. With the advent large synthesis imaging radio telescopes (e.g., Westerbrook Synthesis Telescope (WSRT) and very array (VLA), many solar observations have been made with a high degree angular resolution at microwave decimeter wavelengths. These revealed distinct absence structure on small...
The Pioneer 11 spacecraft encounter with Saturn (closest approach September 1, 1979) has resulted in the discovery of a fully developed magnetosphere high‐energy trapped radiation around Saturn, as reported Science, 207 , 400–453, 1980, by several investigators charged‐particle instruments on spacecraft. present paper contains detail final energetic measurements and new observations obtained from University Chicago instrumentation 11, including overall characteristics electron, proton,...
Temporal variations in the soft X-ray (SXR) emission and radio above solar magnetic network of quiet corona are investigated using Yohkoh SXR images with deep exposure VLA observations centimeter range. The data show several brightenings, an extrapolated occurrence probability one brightening per 3 seconds on total surface. During roughly 10 minutes enhanced flux, radiative losses observed plasma around 1025 ergs event. These events more than order magnitude smaller previously reported...
view Abstract Citations (85) References (43) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Dynamic Spectra of Radio Bursts from Flare Stars Bastian, T. S. ; Bookbinder, J. Dulk, G. A. Davis, M. The Arecibo 305 m telescope has been used to observe radio bursts flare stars at 430 and 1415 MHz. spectra the emission with bandwidths 10 MHz in former case 40 latter are recorded. For AD Leo, microwave burst was 100 percent right circularly polarized, achieved...
view Abstract Citations (49) References (24) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A Search for Cyclotron Maser Radiation from Substellar and Planet-like Companions of Nearby Stars Winglee, Robert M. ; Dulk, George A. Bastian, Timothy S. Several stars within 5 pc have variations in their rectilinear or Keplerian motion that suggest they substellar planetlike companions. However, direct, unambiguous evidence such companions is difficult to obtain. It...
Electrons and protons accelerated trapped in a Saturnian magnetic field have been found by the University of Chicago experiments on Pioneer 11 within 20 Saturn radii ( R s ) planet. In innermost regions, strong absorption effects due to satellites ring material were observed, from ∼ 4 inwards outer edge A at 2.30 (where radiation is absorbed), intensity distributions (≥ 0.5 million electron volts) electrons (2 axially symmetric, consistent with centered dipole aligned planetary rotation...
Magnetic reconnection, the central engine that powers explosive phenomena throughout Universe, is also perceived as one of principal mechanisms for accelerating particles to high energies. Although various signatures magnetic reconnection have been frequently reported, observational evidence links particle acceleration directly site has rare, especially space plasma environments currently inaccessible $\textit{in situ}$ measurements. Here we utilize broadband radio dynamic imaging...
We measured the center-to-limb variation of brightness temperature, $T_b$, from ALMA full-disk images at two frequencies and inverted solution transfer equation to obtain electron $T_e$ as a function optical depth, $τ$. The are very similar AIA 1600Å. temperature center disk is 6180 7250 K 239 100 GHz respectively, with dispersions 170 K. Plage regions stand out clearly in 239/100 intensity ratio, while faculae filament lanes do not. solar radius, reduced 1 AU, $961.1\pm2.5$ arcsec...
view Abstract Citations (100) References (53) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Radio Emission from Chemically Peculiar Stars Linsky, Jeffrey L. ; Drake, Stephen A. Bastian, T. S. In five VLA observing runs the initial survey of radio emission magnetic Bp-Ap stars by Drake et al. is extended to include a total 16 sources detected at 6 cm out 61 observed, giving detection rate 26 percent. Of these stars, three are also 2 cm, four 3.6 and 20 cm....
view Abstract Citations (110) References (46) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Radio Flares from AE Aquarii: A Low-Power Analog to Cygnus X-3? Bastian, T. S. ; Dulk, G. A. Chanmugam, The magnetic cataclysmic variable Aquarii has been observed at 1.5, 4.9, 15, and 22.5 GHz. source shows temporal variations in the flux density, often with a flarelike morphology. are times extreme, values ranging 1-12 mJy 15 GHz; degree of variability increases...
view Abstract Citations (121) References (33) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Discovery of Nonthermal Radio Emission from Magnetic Bp--Ap Stars Drake, Stephen A. ; Abbott, David C. Bastian, T. S. Bieging, J. H. Churchwell, E. Dulk, G. Linsky, Jeffrey L. In a VLA survey chemically peculiar B- and A-type stars with strong magnetic fields, five the 34 observed have been identified as 6 cm continuum sources. Three detections are helium-strong...
We present the first interferometric observation of a zebra-pattern radio burst with simultaneous high spectral (≈1 MHz) and time (20 ms) resolution. The Frequency-Agile Solar Radiotelescope Subsystem Testbed (FST) Owens Valley Array (OVSA) were used in parallel to observe X1.5 flare on 2006 December 14. By using OVSA calibrate FST, source position zebra pattern can be located solar disk. With help multi-wavelength observations nonlinear force-free field extrapolation, is explored relation...
We report observations of type III radio bursts at decimeter wavelengths (type IIIdm bursts) -- signatures suprathermal electron beams propagating in the low corona using new technique dynamic imaging spectroscopy provided by recently upgraded Karl G. Jansky Very Large Array (VLA). For first time, were imaged with high time and frequency resolution over a broad band, allowing beam trajectories to be deduced. Together simultaneous hard X-ray (HXR) extreme ultraviolet (EUV) observations, we...
The archetypical flare star UV Cet was observed by MeerKAT on 5-6 October 2021. A large radio outburst with a duration of $\sim\!2$ hr between 886-1682 MHz time resolution 8s and frequency 0.84 MHz, enabling sensitive dynamic spectra to be formed. emission is characterized three peaks containing multitude broadband arcs or partial in the time-frequency domain. In general, are highly right-hand circularly polarized. During end third peak, brief bursts occur that significantly elliptically We...
Abstract We report observations of solar spicules at millimeter wavelengths (mm- λ ) using the Atacama Large Millimeter/submillimeter Array (ALMA). These are supplemented by in optical, ultraviolet (UV), and extreme (EUV) wavelengths. The were made on 2018 December 25 northern polar coronal hole. ALMA obtained time-resolved imaging 3 mm (100 GHz; 2 s cadence) 1.25 (239 ≈2 minutes with an angular resolution <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">...