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Title: IRIS , Hinode , SDO , and RHESSI Observations of a White Light Flare Produced Directly by Non-thermal Electrons

Abstract

An X1.6 flare occurred in active region AR 12192 on 2014 October 22 at 14:02 UT and was observed by Hinode , IRIS , SDO , and RHESSI . We analyze a bright kernel that produces a white light (WL) flare with continuum enhancement and a hard X-ray (HXR) peak. Taking advantage of the spectroscopic observations of IRIS and Hinode /EIS, we measure the temporal variation of the plasma properties in the bright kernel in the chromosphere and corona. We find that explosive evaporation was observed when the WL emission occurred, even though the intensity enhancement in hotter lines is quite weak. The temporal correlation of the WL emission, HXR peak, and evaporation flows indicates that the WL emission was produced by accelerated electrons. To understand the WL emission process, we calculated the energy flux deposited by non-thermal electrons (observed by RHESSI ) and compared it to the dissipated energy estimated from a chromospheric line (Mg ii triplet) observed by IRIS . The deposited energy flux from the non-thermal electrons is about (3–7.7) × 10{sup 10} erg cm{sup −2} s{sup −1} for a given low-energy cutoff of 30–40 keV, assuming the thick-target model. The energy flux estimated from the changesmore » in temperature in the chromosphere measured using the Mg ii subordinate line is about (4.6–6.7) × 10{sup 9} erg cm{sup −2} s{sup −1}: ∼6%–22% of the deposited energy. This comparison of estimated energy fluxes implies that the continuum enhancement was directly produced by the non-thermal electrons.« less

Authors:
 [1];  [2];  [3];  [4];  [5]
  1. Hinode Science Center, National Astronomical Observatory of Japan (NAOJ), 2-21-1, Osawa, Mitaka, Tokyo 181-8588 (Japan)
  2. Institute for Space–Earth Environmental Research (ISEE), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 466-8550 (Japan)
  3. National Defense Academy of Japan, 1-10-20 Hashirimizu, Yokosuka 239-8686 (Japan)
  4. Hinode team, ISAS/JAXA, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan)
  5. College of Science, George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States)
Publication Date:
OSTI Identifier:
22663791
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 836; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CHROMOSPHERE; COMPARATIVE EVALUATIONS; CORRELATIONS; ELECTRONS; EMISSION; EVAPORATION; HARD X RADIATION; KEV RANGE; PLASMA; SUN; ULTRAVIOLET RADIATION; VISIBLE RADIATION

Citation Formats

Lee, Kyoung-Sun, Imada, Shinsuke, Watanabe, Kyoko, Bamba, Yumi, and Brooks, David H., E-mail: ksun.lee@nao.ac.jp. IRIS , Hinode , SDO , and RHESSI Observations of a White Light Flare Produced Directly by Non-thermal Electrons. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA5B8B.
Lee, Kyoung-Sun, Imada, Shinsuke, Watanabe, Kyoko, Bamba, Yumi, & Brooks, David H., E-mail: ksun.lee@nao.ac.jp. IRIS , Hinode , SDO , and RHESSI Observations of a White Light Flare Produced Directly by Non-thermal Electrons. United States. doi:10.3847/1538-4357/AA5B8B.
Lee, Kyoung-Sun, Imada, Shinsuke, Watanabe, Kyoko, Bamba, Yumi, and Brooks, David H., E-mail: ksun.lee@nao.ac.jp. Mon . "IRIS , Hinode , SDO , and RHESSI Observations of a White Light Flare Produced Directly by Non-thermal Electrons". United States. doi:10.3847/1538-4357/AA5B8B.
@article{osti_22663791,
title = {IRIS , Hinode , SDO , and RHESSI Observations of a White Light Flare Produced Directly by Non-thermal Electrons},
author = {Lee, Kyoung-Sun and Imada, Shinsuke and Watanabe, Kyoko and Bamba, Yumi and Brooks, David H., E-mail: ksun.lee@nao.ac.jp},
abstractNote = {An X1.6 flare occurred in active region AR 12192 on 2014 October 22 at 14:02 UT and was observed by Hinode , IRIS , SDO , and RHESSI . We analyze a bright kernel that produces a white light (WL) flare with continuum enhancement and a hard X-ray (HXR) peak. Taking advantage of the spectroscopic observations of IRIS and Hinode /EIS, we measure the temporal variation of the plasma properties in the bright kernel in the chromosphere and corona. We find that explosive evaporation was observed when the WL emission occurred, even though the intensity enhancement in hotter lines is quite weak. The temporal correlation of the WL emission, HXR peak, and evaporation flows indicates that the WL emission was produced by accelerated electrons. To understand the WL emission process, we calculated the energy flux deposited by non-thermal electrons (observed by RHESSI ) and compared it to the dissipated energy estimated from a chromospheric line (Mg ii triplet) observed by IRIS . The deposited energy flux from the non-thermal electrons is about (3–7.7) × 10{sup 10} erg cm{sup −2} s{sup −1} for a given low-energy cutoff of 30–40 keV, assuming the thick-target model. The energy flux estimated from the changes in temperature in the chromosphere measured using the Mg ii subordinate line is about (4.6–6.7) × 10{sup 9} erg cm{sup −2} s{sup −1}: ∼6%–22% of the deposited energy. This comparison of estimated energy fluxes implies that the continuum enhancement was directly produced by the non-thermal electrons.},
doi = {10.3847/1538-4357/AA5B8B},
journal = {Astrophysical Journal},
number = 2,
volume = 836,
place = {United States},
year = {Mon Feb 20 00:00:00 EST 2017},
month = {Mon Feb 20 00:00:00 EST 2017}
}