Multi-wavelength observations and modelling of a canonical solar flare

Abstract

This paper investigates the temporal evolution of temperature, emission measure, energy loss and velocity in a C-class solar flare from both an observational and theoretical perspective. The properties of the flare were derived by following the systematic cooling of the plasma through the response functions of a number of instruments -- RHESSI (>5 MK), GOES-12 (5-30 MK), TRACE 171 A (1 MK) and SOHO/CDS (~0.03-8 MK). These measurements were studied in combination with simulations from the 0-D EBTEL model. At the flare on-set, upflows of ~90 km s-1 and low level emission were observed in Fe XIX, consistent with pre-flare heating and gentle chromospheric evaporation. During the impulsive phase, upflows of ~80 km s-1 in Fe XIX and simultaneous downflows of 20 km s-1 in He I and O V were observed, indicating explosive chromospheric evaporation. The plasma was subsequently found to reach a peak temperature of ~13 MK in approximately 10 minutes. Using EBTEL, conduction was found to be the dominant loss mechanism during the initial ~300s 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 ~4,000s, radiative losses were determined to dominate over conductive losses. The radiative loss phase was accompanied by significant downflows of <40 km s-1 in O V. 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 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.

10 pages, 7 figures, 2 tables. Accepted for publication in A&A

References in corpus (6)

• Highly Efficient Modeling of Dynamic Coronal Loops
• Observational Evidence for Gentle Chromospheric Evaporation During the Impulsive Phase of a Solar Flare
• Diagnostics of stellar flares from X-ray observations: from the decay to the rise phase
• Dynamics and evolution of an eruptive flare
• A Hot Microflare Observed With RHESSI and Hinode
• Hydrodynamic Simulation of a nano-flare heated multi-strand solar atmospheric loop

Cited by in corpus (12)

• Observing the Roots of Solar Coronal Heating - in the Chromosphere
• Observing the formation of flare-driven coronal rain
• Properties of chromospheric evaporation and plasma dynamics of a solar flare from IRIS observations
• Evidence of Explosive Evaporation in a Microflare Observed by Hinode/EIS
• IRIS Si IV Line Profiles at Flare Ribbons as Indications of Chromospheric Condensation
• Evolution of microflares associated with bright points in coronal holes and in quiet regions
• Plasma heating in the very early and decay phases of solar flares
• Simultaneous Observations of Chromospheric Evaporation and Condensation during a C-class Flare
• Modeling properties of chromospheric evaporation driven by thermal conduction fronts from reconnection shocks
• Interpreting Helioseismic Structure Inversion Results of Solar Active Regions
• Onset of Electron Acceleration in a Flare Loop
• Tracking the motion of a shock along a channel in the low solar corona