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Title: Measuring Velocities in the Early Stage of an Eruption: Using “Overlappogram” Data from Hinode EIS

Abstract

In order to understand the onset phase of a solar eruption, plasma parameter measurements in the early phases are key to constraining models. There are two current instrument types that allow us to make such measurements: narrow-band imagers and spectrometers. In the former case, even narrow-band filters contain multiple emission lines, creating some temperature confusion. With imagers, however, rapid cadences are achievable and the field of view can be large. Velocities of the erupting structures can be measured by feature tracking. In the spectrometer case, slit spectrometers can provide spectrally pure images by “rastering” the slit to build up an image. This method provides limited temporal resolution, but the plasma parameters can be accurately measured, including velocities along the line of sight. Both methods have benefits and are often used in tandem. In this paper we demonstrate for the first time that data from the wide slot on the Hinode EUV Imaging Spectrometer, along with imaging data from AIA, can be used to deconvolve velocity information at the start of an eruption, providing line-of-sight velocities across an extended field of view. Using He ii 256 Å slot data at flare onset, we observe broadening or shift(s) of the emission linemore » of up to ±280 km s{sup −1}. These are seen at different locations—the redshifted plasma is seen where the hard X-ray source is later seen (energy deposition site). In addition, blueshifted plasma shows the very early onset of the fast rise of the filament.« less

Authors:
; ; ;  [1];  [2]; ;  [3]
  1. UCL-Mullard Space Science Laboratory Holmbury St Mary, Dorking, Surrey, RH5 6NT (United Kingdom)
  2. National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo 181-8588 (Japan)
  3. Space Science Division, Naval Research Laboratory, 4555 Overlook Avenue, SW, Washington, DC 20375 (United States)
Publication Date:
OSTI Identifier:
22663506
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 842; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; EMISSION; ENERGY ABSORPTION; ENERGY LOSSES; EXTREME ULTRAVIOLET RADIATION; FILTERS; HARD X RADIATION; PLASMA; RED SHIFT; RESOLUTION; SPECTROMETERS; SUN; VELOCITY; X-RAY SOURCES

Citation Formats

Harra, Louise K., Matthews, Sarah, Culhane, J. Leonard, Woods, Magnus M., Hara, Hirohisa, Doschek, George A., and Warren, Harry, E-mail: l.harra@ucl.ac.uk. Measuring Velocities in the Early Stage of an Eruption: Using “Overlappogram” Data from Hinode EIS. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA7411.
Harra, Louise K., Matthews, Sarah, Culhane, J. Leonard, Woods, Magnus M., Hara, Hirohisa, Doschek, George A., & Warren, Harry, E-mail: l.harra@ucl.ac.uk. Measuring Velocities in the Early Stage of an Eruption: Using “Overlappogram” Data from Hinode EIS. United States. doi:10.3847/1538-4357/AA7411.
Harra, Louise K., Matthews, Sarah, Culhane, J. Leonard, Woods, Magnus M., Hara, Hirohisa, Doschek, George A., and Warren, Harry, E-mail: l.harra@ucl.ac.uk. Sat . "Measuring Velocities in the Early Stage of an Eruption: Using “Overlappogram” Data from Hinode EIS". United States. doi:10.3847/1538-4357/AA7411.
@article{osti_22663506,
title = {Measuring Velocities in the Early Stage of an Eruption: Using “Overlappogram” Data from Hinode EIS},
author = {Harra, Louise K. and Matthews, Sarah and Culhane, J. Leonard and Woods, Magnus M. and Hara, Hirohisa and Doschek, George A. and Warren, Harry, E-mail: l.harra@ucl.ac.uk},
abstractNote = {In order to understand the onset phase of a solar eruption, plasma parameter measurements in the early phases are key to constraining models. There are two current instrument types that allow us to make such measurements: narrow-band imagers and spectrometers. In the former case, even narrow-band filters contain multiple emission lines, creating some temperature confusion. With imagers, however, rapid cadences are achievable and the field of view can be large. Velocities of the erupting structures can be measured by feature tracking. In the spectrometer case, slit spectrometers can provide spectrally pure images by “rastering” the slit to build up an image. This method provides limited temporal resolution, but the plasma parameters can be accurately measured, including velocities along the line of sight. Both methods have benefits and are often used in tandem. In this paper we demonstrate for the first time that data from the wide slot on the Hinode EUV Imaging Spectrometer, along with imaging data from AIA, can be used to deconvolve velocity information at the start of an eruption, providing line-of-sight velocities across an extended field of view. Using He ii 256 Å slot data at flare onset, we observe broadening or shift(s) of the emission line of up to ±280 km s{sup −1}. These are seen at different locations—the redshifted plasma is seen where the hard X-ray source is later seen (energy deposition site). In addition, blueshifted plasma shows the very early onset of the fast rise of the filament.},
doi = {10.3847/1538-4357/AA7411},
journal = {Astrophysical Journal},
number = 1,
volume = 842,
place = {United States},
year = {Sat Jun 10 00:00:00 EDT 2017},
month = {Sat Jun 10 00:00:00 EDT 2017}
}