• Title/Summary/Keyword: Flare

Search Result 481, Processing Time 0.032 seconds

Analysis of Solar Microwave Burst Spectrum, I. Nonuniform Magnetic Field

  • Lee, Jeongwoo
    • Journal of Astronomy and Space Sciences
    • /
    • v.35 no.4
    • /
    • pp.211-218
    • /
    • 2018

  • Solar microwave bursts carry information about the magnetic field in the emitting region as well as about electrons accelerated during solar flares. While this sensitivity to the coronal magnetic field must be a unique advantage of solar microwave burst observations, it also adds a complexity to spectral analysis targeted to electron diagnostics. This paper introduces a new spectral analysis procedure in which the cross-section and thickness of a microwave source are expressed as power-law functions of the magnetic field so that the degree of magnetic inhomogeneity can systematically be derived. We applied this spectral analysis tool to two contrasting events observed by the Owens Valley Solar Array: the SOL2003-04-04T20:55 flare with a steep microwave spectrum and the SOL2003-10-19T16:50 flare with a broader spectrum. Our analysis shows that the strong flare with the broader microwave spectrum occurred in a region of highly inhomogeneous magnetic field and vice versa. We further demonstrate that such source properties are consistent with the magnetic field observations from the Michelson Doppler Imager instrument onboard the Solar and Heliospheric Observatory (SOHO) spacecraft and the extreme ultraviolet imaging observations from the SOHO extreme ultraviolet imaging telescope. This spectral inversion tool is particularly useful for analyzing microwave flux spectra of strong flares from magnetically complex systems.

  • https://doi.org/10.5140/JASS.2018.35.4.211 인용 PDF KSCI HTML

He I D3 and 10830 observations of the flare-productive active region AR 12673 on 2017 September 7

  • Kim, Yeon-Han;Xu, Yan;Kim, Sujin;Bong, Su-Chan;Lim, Eun-Kyung;Yang, Heesu;Yurchyshyn, Vasyl;Ahn, Kwangsu;Park, Young-Deuk;Goode, Phillip R.
    • The Bulletin of The Korean Astronomical Society
    • /
    • v.43 no.2
    • /
    • pp.46.2-46.2
    • /
    • 2018

  • The active region NOAA AR 12673 is the most flare productive active region in the solar cycle 24. On 2017 September 07, it produced an X1.3 flare, three M-class, and several C-class flares. We successfully observed several C-class flares from 16:50 UT to 22:00 UT using the 1.6m Goode Solar Telescope (GST; formerly NST) at Big Bear Solar Observatory (BBSO). The GST provides us with unprecedented high-resolution data of the Sun since 2009. Interestingly, we observed the active region in He I D3 and 10830 lines simultaneously. The data shows several interesting features: (1) D3 emission seems to be much weaker than 10830 emission around 21:29 UT; (2) a small loop seen in 10830 is moving upward and is brightened around 21:16 UT, but it is not clear in D3; (3) there are waves in the penumbra seen in 10830 line center; (4) there is a jet with twisting motion. In this presentation, we will give the results of our analysis and interpretations.

  • PDF

Evaluation of Impact Loads Associated with Flare Slamming (플레어 슬래밍에 관련된 충격하중의 계산)

  • Troesch, Arimin W.;Kang, Chang-Gu
    • Bulletin of the Society of Naval Architects of Korea
    • /
    • v.27 no.3
    • /
    • pp.56-72
    • /
    • 1990

  • The hydrodynamic aspects of bow flare impact are discussed and the assumptions implicit in typical flare impact calculations are examined. Calculations based upon a pressure release free surface boundary condition are presented. While this simplified boundary condition eliminates the possibility of important factors such as splash-up and above-surface wetting, it has the significant advantage of being computationally simple. Both three-dimensional and two-dimensional results are compared with experiments. Errors resulting from the approximate free surface condition are examined. Also included in the two-dimensional and three-dimensional analysis are longitudinal distributions of the vertical bending moment and vertical shear force.

  • PDF