A5052995056- Solar and Space Plasma Dynamics
- Ionosphere and magnetosphere dynamics
- Astro and Planetary Science
- Stellar, planetary, and galactic studies
- Geomagnetism and Paleomagnetism Studies
- Solar Radiation and Photovoltaics
- Gamma-ray bursts and supernovae
- Geophysics and Gravity Measurements
- History and Developments in Astronomy
- Magnetic confinement fusion research
- Atmospheric Ozone and Climate
- Photovoltaic System Optimization Techniques
- Earthquake Detection and Analysis
- Solar Thermal and Photovoltaic Systems
- Global Energy and Sustainability Research
- Oil, Gas, and Environmental Issues
- Calibration and Measurement Techniques
- Astronomical Observations and Instrumentation
- Fluid Dynamics and Turbulent Flows
- Graphite, nuclear technology, radiation studies
- Geology and Paleoclimatology Research
- Aerodynamics and Acoustics in Jet Flows
- Nuclear Physics and Applications
- Astrophysics and Cosmic Phenomena
- Plasma and Flow Control in Aerodynamics
Marshall Space Flight Center
2015-2024
Heliophysics
2012-2019
University of St Andrews
2015
Japan Aerospace Exploration Agency
2007-2013
National Space Science and Technology Center
2002-2013
U.S. National Science Foundation
2008
Institute of Space and Astronautical Science
1995-2007
Applied Technologies (United States)
2001-2003
National Academy of Sciences
2000-2001
National Academies of Sciences, Engineering, and Medicine
2000-2001
We present observations of the magnetic field configuration and its transformation in six solar eruptive events that show good agreement with standard bipolar model for flares. The are X-ray images from Yohkoh soft telescope (SXT) magnetograms Kitt Peak National Solar Observatory, interpreted together 1-8 Å flux observed by GOES. yield following interpretation. (1) Each event is a explosion occurs an initially closed single bipole which core sheared twisted shape sigmoid, having oppositely...
By examining many X-ray jets in Hinode/X-Ray Telescope coronal movies of the polar holes, we found that there is a dichotomy jets. About two thirds fit standard reconnection picture for jets, and about one third are another type. We present observations indicating non-standard counterparts erupting-loop Hα macrospicules, which jet-base magnetic arch undergoes miniature version blowout eruptions produce major mass ejections. From detail typical were also caught He ii 304 Å snapshots from...
We present EUV solar observations showing evidence for omnipresent jetting activity driven by small-scale magnetic reconnection at the base of corona. argue that physical mechanism heats and drives wind its source is ubiquitous in form (i.e., a.k.a. jetlets). This activity, like heating coronal plasma, are regardless cycle phase. Each event arises from opposite polarity fields producing a short-lived jet hot plasma Alfv\'en waves into The discrete nature these jetlet events leads to...
A sudden depletion or intensity "dimming" of the X-ray corona sometimes accompanies a solar eruptive flare coronal mass ejection (CME). We have identified dimming that occurred just prior to "halo" CME, observed on 1997 April 7 using Soft Telescope (SXT) Yohkoh. Halo CMEs are prime candidates for "space weather" effects. The in compact regions near 14 UT 7, over projected area about 1020 cm-2, and indicate few times 1014 g was ejected. This is lower limit imposed by obscuration volume...
Spicules are rapidly evolving fine-scale jets of magnetized plasma in the solar chromosphere. It remains unclear how these prevalent originate from surface and what role they play heating atmosphere. Using Goode Solar Telescope at Big Bear Observatory, we observed spicules emerging within minutes appearance opposite-polarity magnetic flux around dominant-polarity field concentrations. Data Dynamics Observatory showed subsequent adjacent corona. The dynamic interaction fields (likely due to...
ABSTRACT We report observations of 10 random on-disk solar quiet-region coronal jets found in high-resolution extreme ultraviolet (EUV) images from the Solar Dynamics Observatory ( SDO )/Atmospheric Imaging Assembly and having good coverage magnetograms /Helioseismic Magnetic Imager (HMI). Recent studies show that are driven by eruption a small-scale filament (called minifilament ). However, trigger these eruptions is still unknown. In present study, we address question: what leads to...
We present results from a study of 54 polar X-ray jets that were observed in coronal movies the Telescope on Hinode and had simultaneous coverage cooler transition region (T ∼ 105 K) taken He ii 304 Å band Atmospheric Imaging Assembly (AIA) Solar Dynamics Observatory. These dual observations verify standard-jet/blowout-jet dichotomy previously found primarily XRT alone. In accord with models blowout standard jets, AIA show cool component nearly all small minority obvious lateral expansion...
ABSTRACT We present observations of eruptive events in an active region adjacent to on-disk coronal hole on 2012 June 30, primarily using data from the Solar Dynamics Observatory ( SDO )/Atmospheric Imaging Assembly (AIA), /Helioseismic and Magnetic Imager (HMI), STEREO - B . One eruption is a large-scale (∼100″) filament that typical other eruptions, showing slow-rise onset followed by faster-rise motion starting as flare emissions begin. It also shows “EUV crinkle” emission pattern,...
The Daniel K. Inouye Solar Telescope (DKIST) will revolutionize our ability to measure, understand and model the basic physical processes that control structure dynamics of Sun its atmosphere. first-light DKIST images, released publicly on 29 January 2020, only hint at extraordinary capabilities which accompany full commissioning five facility instruments. With this Critical Science Plan (CSP) we attempt anticipate some what those enable, providing a snapshot scientific pursuits hopes engage...
Abstract Hinode is Japan’s third solar mission following Hinotori (1981–1982) and Yohkoh (1991–2001): it was launched on 2006 September 22 in operation currently. carries three instruments: the Solar Optical Telescope, X-Ray EUV Imaging Spectrometer. These instruments were built under international collaboration with National Aeronautics Space Administration UK Science Technology Facilities Council, its has been contributed to by European Agency Norwegian Center. After describing satellite...
A solar flare was observed on 1997 April 7 with the Soft X-ray Telescope (SXT) Yohkoh. The associated a "halo" coronal mass ejection (CME). flaring region showed areas of reduced soft (SXR) brightness—"dimmings"—that developed prior to CME in white light and persisted for several hours following CME. most prominent dimming regions were located near ends preflare SXR S-shaped (sigmoid) feature that disappeared during event, leaving behind postflare arcade cusp structure. Based upon these...
Using the Yohkoh soft X‐ray images, we examine coronal structures associated with “halo” mass ejections (CMEs). These may correspond to events near solar disk center. Starting a list of eleven confirmed halo CMEs over time range from December 1996 through May 1997, find seven surface features identifiable in X‐rays, GOES classifications ranging A1 M1.3. have characteristic pattern sigmoid → arcade development. In each these events, pre‐flare structure disrupted during flare, leaving...
One signature of expulsion coronal mass ejections (CMEs) from the solar corona is appearance transient intensity dimmings in images. These have generally been assumed to be due discharge CME material corona, and thus "dimming regions" are thought as an important sources CMEs. We present spectral observations two dimming regions at time CMEs, using Coronal Diagnostic Spectrometer (CDS) on SOHO satellite. limb associated with a traveling plane sky, while other region disk Earth-directed "halo"...
A subset of the solar-disk counterparts to halo coronal mass ejections (CMEs) displays an evolution in soft X-rays (SXR) that is characterized by a preflare S-shaped structure, dubbed "sigmoid," which evolves into postflare cusp or arcade. We examine morphological properties sigmoids cusps and arcades for four such regions associated with SXR flares, using Soft X-Ray Telescope (SXT) on Yohkoh satellite EUV Imaging (EIT) Solar Heliospheric Observatory (SOHO) satellite. Most our EIT...
We observe the eruption of an active-region solar filament on 1998 July 11 using high time cadence and spatial resolution EUV observations from TRACE satellite, along with soft X-ray images telescope (SXT) Yohkoh hard fluxes BATSE instrument CGRO satellite (HXT) Yohkoh, ground-based magnetograms. concentrate initiation in effort to understand mechanism. Prior undergoes a slow upward movement slow-rise phase approximately constant velocity ≈15 km s-1 that lasts about 10 minutes. It then...
We present a three-dimensional density model of coronal prominence cavities, and morphological fit that has been tightly constrained by uniquely well-observed cavity. Observations were obtained as part an International Heliophysical Year campaign instruments from variety space- ground-based observatories, spanning wavelengths radio to soft X-ray integrated white light. From these data it is clear the cavity limb manifestation longitudinally extended polar-crown filament channel, region low...
We examine the three-dimensional magnetic structure and dynamics of a solar EUV-macrospicule jet that occurred on 2011 February 27 in an on-disk coronal hole. The observations are from Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly (AIA) SDO Helioseismic Magnetic Imager (HMI). reveal this event, closed-field-carrying cool absorbing plasma, as erupting mini-filament, erupted opened, forming blowout jet. Contrary to some models, there was no substantial recently emerged, closed,...
We investigate the origin of ten solar quiet region pre-jet minifilaments, using EUV images from SDO/AIA and magnetograms SDO/HMI. recently found panesar16b that coronal jets are driven by minifilament eruptions, where those eruptions result flux cancelation at magnetic neutral line under minifilament. Here, we study longer-term minifilaments themselves. find they between minority-polarity majority-polarity patches. In each regions, opposite-polarity patches converge cancel, with a reduction...
Abstract The Parker Solar Probe (PSP) has observed copious rapid magnetic field direction changes in the near-Sun solar wind. These features have been called “switchbacks,” and their origin is a mystery. But widespread nature suggests that they may be generated by frequently occurring process Sun’s atmosphere. We examine possibility switchbacks originate from coronal jets. Recent work many jets result when photospheric flux cancels, forms small-scale “minifilament” rope erupts reconnects...
Abstract We study a series of X-ray-bright, rapidly evolving active region coronal jets outside the leading sunspot AR 12259, using Hinode /X-ray telescope, Solar Dynamics Observatory (SDO) /Atmospheric Imaging Assembly (AIA) and Helioseismic Magnetic Imager (HMI), Interface Region Spectrograph ( IRIS ) data. The detailed evolution such “violent” remained mystery after our previous investigation jets. we investigate here erupt from three localized subregions, each containing (positive)...
From Hinode observations of solar X-ray jets, Type-II spicules, and granule-size emerging bipolar magnetic fields in quiet regions coronal holes, we advocate a scenario for powering heating the wind. In this scenario, spicules Alfvén waves are generated by bipoles (EBs) manner generation jets larger bipoles. estimate that their co-generated carry into corona an area-average flux mechanical energy ∼7 × 105 erg cm−2 s−1. This is enough to power wind therefore indicates EBs main engines...
We study 14 large solar jets observed in polar coronal holes. In EUV movies from the Solar Dynamics Observatory/Atmospheric Imaging Assembly (AIA), each jet appears similar to most X-ray and that erupt holes; but is exceptional it goes higher than most, so high outer corona beyond 2.2 RSun images Heliospheric Observatory/Large Angle Spectroscopic Coronagraph (LASCO)/C2 coronagraph. From AIA He ii 304 Å LASCO/C2 running-difference of these high-reaching jets, we find: (1) front transits below...