Browsing by Author "Winebarger, Amy R."

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    Determining the Nanoflare Heating Frequency of an X-Ray Bright Point Observed by MaGIXS
    (IOP Publishing, 2024) Mondal, Biswajit; Athiray, P. S.; Winebarger, Amy R.; Savage, Sabrina L.; Kobayashi, Ken; Bradshaw, Stephen; Barnes, Will; Champey, Patrick R.; Cheimets, Peter; Dudík, Jaroslav; Golub, Leon; Mason, Helen E.; McKenzie, David E.; Moore, Christopher S.; Madsen, Chad; Reeves, Katharine K.; Testa, Paola; Vigil, Genevieve D.; Warren, Harry P.; Walsh, Robert W.; Zanna, Giulio Del
    Nanoflares are thought to be one of the prime candidates that can heat the solar corona to its multimillion kelvin temperature. Individual nanoflares are difficult to detect with the present generation of instruments, but their presence can be inferred by comparing simulated nanoflare-heated plasma emissions with the observed emission. Using HYDRAD coronal loop simulations, we model the emission from an X-ray bright point (XBP) observed by the Marshall Grazing Incidence X-ray Spectrometer (MaGIXS), along with the nearest available observations from the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO) and the X-Ray Telescope (XRT) on board the Hinode observatory. The length and magnetic field strength of the coronal loops are derived from the linear force-free extrapolation of the observed photospheric magnetogram by the Helioseismic and Magnetic Imager on board SDO. Each loop is assumed to be heated by random nanoflares, whose magnitude and frequency are determined by the loop length and magnetic field strength. The simulation results are then compared and matched against the measured intensity from AIA, XRT, and MaGIXS. Our model results indicate the observed emission from the XBP under study could be well matched by a distribution of nanoflares with average delay times 1500–3000 s. Further, we demonstrate the high sensitivity of MaGIXS and XRT for diagnosing the heating frequency using this method, while AIA passbands are found to be the least sensitive.
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    The First Flight of the Marshall Grazing Incidence X-Ray Spectrometer (MaGIXS)
    (IOP Publishing, 2023) Savage, Sabrina L.; Winebarger, Amy R.; Kobayashi, Ken; Athiray, P. S.; Beabout, Dyana; Golub, Leon; Walsh, Robert W.; Beabout, Brent; Bradshaw, Stephen; Bruccoleri, Alexander R.; Champey, Patrick R.; Cheimets, Peter; Cirtain, Jonathan; DeLuca, Edward E.; Zanna, Giulio Del; Dudík, Jaroslav; Guillory, Anthony; Haight, Harlan; Heilmann, Ralf K.; Hertz, Edward; Hogue, William; Kegley, Jeffery; Kolodziejczak, Jeffery; Madsen, Chad; Mason, Helen; McKenzie, David E.; Ranganathan, Jagan; Reeves, Katharine K.; Robertson, Bryan; Schattenburg, Mark L.; Scholvin, Jorg; Siler, Richard; Testa, Paola; Vigil, Genevieve D.; Warren, Harry P.; Watkinson, Benjamin; Weddendorf, Bruce; Wright, Ernest
    The Marshall Grazing Incidence X-ray Spectrometer (MaGIXS) sounding rocket experiment launched on 2021 July 30 from the White Sands Missile Range in New Mexico. MaGIXS is a unique solar observing telescope developed to capture X-ray spectral images of coronal active regions in the 6–24 Å wavelength range. Its novel design takes advantage of recent technological advances related to fabricating and optimizing X-ray optical systems, as well as breakthroughs in inversion methodologies necessary to create spectrally pure maps from overlapping spectral images. MaGIXS is the first instrument of its kind to provide spatially resolved soft X-ray spectra across a wide field of view. The plasma diagnostics available in this spectral regime make this instrument a powerful tool for probing solar coronal heating. This paper presents details from the first MaGIXS flight, the captured observations, the data processing and inversion techniques, and the first science results.
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    The origin of reconnection-mediated transient brightenings in the solar transition region
    (Springer Nature, 2021) Bahauddin, Shah Mohammad; Bradshaw, Stephen J.; Winebarger, Amy R.
    The ultraviolet emission from the solar transition region is dominated by dynamic, low-lying magnetic loops. The enhanced spatial and temporal resolution of the solar observation satellite Interface Region Imaging Spectrograph (IRIS) has made it possible to study these structures in fine detail. IRIS has observed ‘transient brightenings’ in these loops, associated with strong excess line broadenings1,2 providing important clues to the mechanisms that heat the solar atmosphere. However, the physical origin of the brightenings is debated. The line broadenings have been variously interpreted as signatures of nanoflares3, magneto-hydrodynamic turbulence4, plasmoid instabilities5 and magneto-acoustic shocks6. Here we use IRIS slit-jaw images and spectral data, and the Atmospheric Imaging Assembly of the Solar Dynamics Observatory spacecraft, to show that the brightenings are consistent with magnetic-reconnection-mediated impulsive heating at field-line braiding sites in multi-stranded transition-region loops. The spectroscopic observations present evidence for preferential heating of heavy ions from the transition region and we show that this is consistent with ion cyclotron turbulence caused by strong currents at the reconnection sites. Time-dependent differential emission measure distributions are used to determine the heating frequency7,8,9 and to identify pockets of faintly emitting ‘super-hot’ plasma. The observations we present and the techniques we demonstrate open up a new avenue of diagnostics for reconnection-mediated energy release in solar plasma.