Title: Intensity Variations in EIT Shutterless Mode: Waves or Flows?
Authors: De Groof, Anik
Berghmans, David
Van Driel-Gesztelyi, Lidia
Poedts, Stefaan #
Issue Date: Jan-2004
Publisher: ESA Publications Division
Host Document: ESA SP vol:547 pages:245-250
Conference: SOHO 13 - Waves, Oscillations and Small-Scale Transient Events in the Solar Atmosphere: A Joint View from SOHO and TRACE location:Palma de Mallorca, Balearic Islands, Spain date:29 September - 3 October 2003
Abstract: On 11 July 2001 an EIT shutterless campaign was conducted which provided 120 high-cadence (68s) 304 Å images of the north eastern quarter of the Sun. The most interesting feature seen in the data is an off-limb half loop structure along which systematic intensity variations appear to propagate from the top of the loop towards its footpoint. We investigate the underlying cause of these propagating disturbances, i.e. whether they are caused by waves or by plasma flows. First we identify 7 blobs with the highest intensities and follow them along the loop. By means of a location-time plot, bulk velocities can be measured at several locations along the loop. The velocity curve found this way is then compared with characteristic wave speeds and with the free-fall speed in order to deduce the nature of the intensity variations. Additional information is derived by measuring the relative intensity enhancements and comparing the EIT 304 Å sequence with Big Bear and 171 Å data. The idea of slow magneto-acoustic waves is rejected, and we find several arguments supporting that these intensity variations are due to flowing/falling plasma blobs.
ISBN: 92-9092-858-1
Publication status: published
KU Leuven publication type: IC
Appears in Collections:Plasma-astrophysics Section
# (joint) last author

Files in This Item:
File Description Status SizeFormat
procpalma2003.pdfMain article Published 313KbAdobe PDFView/Open


All items in Lirias are protected by copyright, with all rights reserved.