A simple model of chromospheric evaporation and condensation driven conductively in a solar flare

Abstract

Magnetic energy released in the corona by solar flares reaches the chromosphere where it drives characteristic upflows and downflows known as evaporation and condensation. These flows are studied here for the case where energy is transported to the chromosphere by thermal conduction. An analytic model is used to develop relations by which the density and velocity of each flow can be predicted from coronal parameters including the flare's energy flux $F$. These relations are explored and refined using a series of numerical investigations in which the transition region is represented by a simplified density jump. The maximum evaporation velocity, for example, is well approximated by $v_e\simeq 0.38(F/{\rho }_{co,0}{)}^{1/3}$, where ${\rho }_{co,0}$ is the mass density of the pre-flare corona. This and the other relations are found to fit simulations using more realistic models of the transition region both performed in this work, and taken from a variety of previously published investigations. These relations offer a novel and efficient means of simulating coronal reconnection without neglecting entirely the effects of evaporation.

References in corpus (10)

• Radiative Hydrodynamic Models of the Optical and Ultraviolet Emission from Solar Flares
• Velocity Characteristics of Evaporated Plasma Using Hinode/EIS
• RHESSI Observation of Chromospheric Evaporation
• Evolution of the Loop-Top Source of Solar Flares--Heating and Cooling Processes
• Gas-dynamic shock heating of post-flare loops due to retraction following localized, impulsive reconnection
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• Shocks and Thermal Conduction Fronts in Retracting Reconnected Flux Tubes
• Numerical examination of plasmoid-induced reconnection model for solar flares: the relation between plasmoid velocity and reconnection rate
• Slow shocks and conduction fronts from Petschek reconnection of skewed magnetic fields: two-fluid effects
• Modeling properties of chromospheric evaporation driven by thermal conduction fronts from reconnection shocks

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• Hydrogen Balmer Line Broadening in Solar and Stellar Flares
• Magnetohydrodynamic shocks in and above post-flare loops: two-dimensional simulation and a simplified model
• APO & SMARTS flare star campaign observations I. Blue wing asymmetries in chromospheric lines during mid M dwarf flares from simultaneous spectroscopic and photometric observation data
• A Seven-Day Multi-Wavelength Flare Campaign on AU Mic I: High-Time Resolution Light Curves and the Thermal Empirical Neupert Effect
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• Correlated Spatiotemporal Evolution of Extreme-Ultraviolet Ribbons and Hard X-rays in a Solar Flare
• A Superflare on YZ Canis Minoris Observed by Seimei Telescope and TESS: Red Asymmetry of H$\alpha$ Emission Associated with White-Light Emission
• How gas-dynamic flare models powered by Petschek reconnection differ from those with ad hoc energy sources
• The Neupert Effect of Flare UltraViolet and Soft X-ray Emissions
• Observation and Modeling of Chromospheric Evaporation in a Coronal Loop Related to Active Region Transient Brightening
• Connecting Chromospheric Condensation Signatures to Reconnection Driven Heating Rates in an Observed Flare
• A reconnection-driven model of the hard X-ray loop-top source from flare 2004-Feb-26
• Red Asymmetry of H${}_{\alpha }$ Line Profiles during the flares on the active RS CVn-type star II Pegasi
• Call and Response: A Time-Resolved Study of Chromospheric Evaporation in a Large Solar Flare
• Impact of thermal misbalance on acoustic-gravity waves in the solar atmosphere
• Thermodynamic properties of small flares in the quiet Sun observed by H$\alpha$ and EUV: plasma motion of the chromosphere and time evolution of temperature/emission measure
• Tracing Field Lines That Are Reconnecting or Expanding or Both
• A new view of the solar interface region from the Interface Region Imaging Spectrograph (IRIS)