Volume 494, Number 3, February II 2009
|Page(s)||1127 - 1136|
|Published online||11 December 2008|
Multi-wavelength observations and modelling of a canonical solar flare
Astrophysics Research Group, School of Physics, Trinity College Dublin, Dublin 2, Ireland e-mail: email@example.com
2 Solar Physics Laboratory (Code 671), Heliophysics Science Division, NASA Goddard Space Flight Centre, Greenbelt, MD 20771, USA
Accepted: 5 December 2008
Aims. We investigate the temporal evolution of temperature, emission measure, energy loss, and velocity in a C-class solar flare from both observational and theoretical perspectives.
Methods. The properties of the flare were derived by following the systematic cooling of the plasma through the response functions of a number of instruments – the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI; >5 MK), GOES-12 (5–30 MK), the Transition Region and Coronal Explorer (TRACE 171 Å; 1 MK), and the Coronal Diagnostic Spectrometer (CDS; ~0.03–8 MK). These measurements were studied in combination with simulations from the 0-D enthalpy based thermal evolution of loops (EBTEL) model.
Results. At the flare onset, upflows of ~90 km s-1 and low-level emission were observed in , consistent with pre-flare heating and gentle chromospheric evaporation. During the impulsive phase, upflows of ~80 km s-1 in and simultaneous downflows of ~20 km s-1 in and were observed, indicating explosive chromospheric evaporation. The plasma was subsequently found to reach a peak temperature of 13 MK in approximately 10 min. Using EBTEL, conduction was found to be the dominant loss mechanism during the initial ~300 s of the decay phase. It was also found to be responsible for driving gentle chromospheric evaporation during this period. As the temperature fell below ~8 MK, and for the next ~4000 s, radiative losses were determined to dominate over conductive losses. The radiative loss phase was accompanied by significant downflows of ≤40 km s-1 in .
Conclusions. This is the first extensive study of the evolution of a canonical solar flare using both spectroscopic and broad-band instruments in conjunction with a 0-D hydrodynamic model. While our results are in broad agreement with the standard flare model, the simulations suggest that both conductive and non-thermal beam heating play important roles in heating the flare plasma during the impulsive phase of at least this event.
Key words: Sun: flares / hydrodynamics
© ESO, 2009
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.