Sign on

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Also-Read Articles (Reads History)
·
· Translate This Page
Title:
Observation of the Conversion From Explosive to Gentle Chromospheric Evaporation During a Solar Flare
Authors:
Brosius, Jeffrey W.
Affiliation:
AA(Catholic University of America at NASA/GSFC)
Publication:
American Astronomical Society, SPD meeting #40, #36.03; Bulletin of the American Astronomical Society, Vol. 41, p.868
Publication Date:
05/2009
Origin:
AAS
Bibliographic Code:
2009SPD....40.3603B

Abstract

A GOES M1.5 solar flare was observed in NOAA AR 10652 on 27 July 2004 around 20:00 UT with SOHO. EIT images show that the CDS slit was positioned within the flare, whose emission extended 1 arcmin along the slit. Rapid cadence (9.8 s) stare spectra obtained with CDS include emission from the chromosphere (He I at 584.3 A), transition region (O V at 629.7 A), corona (Si XII at 520.7 A), and hot flare plasma (Fe XIX at 592.2 A), and reveal that (1) the flare brightened in its southern parts before it did so in the north; (2) chromospheric evaporation was "explosive" during the first rapid intensity increase observed in Fe XIX, but converted to "gentle" during the second; (3) chromospheric evaporation did not occur in the northern portion of the flare observed by CDS: the brightening observed there was due to flare material moving into that location from elsewhere. The initial slow, steady increase of Fe XIX intensity that was observed to start several minutes before its rapid increase may have been due to direct coronal heating. The change from explosive to gentle evaporation was likely due to either an increased absorption of beam energy during the gentle event because the beam passed through an atmosphere modified by the earlier explosive event, or to a weakening of the coronal magnetic field's ability to accelerate nonthermal particle beams (via reconnection) as the flare progressed, or both. This work is supported by NASA grant NNX07AI09G.
Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)
   

Find Similar Abstracts:

Use: Authors
Title
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints