E-Print Archive

There are 4451 abstracts currently viewable.


Search:

Advanced Search
Options
Main Page Add New E-Print Submitter
Information
Feedback
News Help/FAQ About Preferences
Manage Key Phrase
Notification
Plasma dynamics in the flaring loop observed by RHESSI View all abstracts by submitter

Tomasz Mrozek   Submitted: 2022-01-07 03:47

Hard X-rays (HXRs) contain the most direct information about the non-thermal electron population in solar flares. The approximation of the HXR emission mechanism (bremsstrahlung), known as the thick-target model, is well developed. It allows one to diagnose the physical conditions within a flaring structure. The thick-target model predicts that in flare foot points, we should observe lowering of HXR sources' altitude with increasing energy. The foot point of HXR sources result from the direct interaction of non-thermal electron beams with plasma in the lower part of the solar atmosphere, where the density increases rapidly. Therefore, we can estimate the plasma density distribution along the non-thermal electron beam directly from the observations of the altitude-energy relation obtained for the HXR foot point sources. However, the relation is not only density-dependent. Its shape is also determined by the power-law distribution of non-thermal electrons. Additionally, during the impulsive phase, the plasma density and a degree of ionisation within foot points may change dramatically due to heating and chromospheric evaporation. For this reason, the interpretation of observed HXR foot point sources' altitudes is not straightforward and needs detailed numerical modelling of the electron precipitation process. We present the results of numerical modelling of one well-observed solar flare. We used HXR observations obtained by RHESSI. The numerical model was calculated using the hydrodynamic 1D model with an application of the Fokker-Planck formalism for non-thermal beam precipitation. HXR data were used to trace chromospheric density changes during a non-thermal emission burst, in detail. We have found that the amount of mass that evaporated from the chromosphere is in the range of 2.7x1013-4.0x1014{g}. This is in good agreement with the ranges obtained from hydrodynamical modelling of a flaring loop (2.3x1013-3.3x1013{g}), and from an analysis of observed emission measure in the loop top (3.9x1013-5.3x1013{g}). Additionally, we used specific scaling laws which gave another estimation of the evaporated mass around 2x1014{g}. Consistency between the obtained values shows that HXR images may provide an important constraint for models - a mass of plasma that evaporated due to a non-thermal electron beam depositing energy in the chromosphere. High-energy, non-thermal sources' (above 20 keV in this case) positions fit the column density changes obtained from the hydrodynamical model perfectly. Density changes seem to be less affected by the electrons' spectral index. The obtained results significantly improve our understanding of non-thermal electron beam precipitation and allow us to refine the energy balance in solar flare foot points during the impulsive phase.

Authors: Mrozek, T., Falewicz, R., Kołomański, S., Litwicka, M.
Projects: RHESSI

Publication Status: A&A accepted
Last Modified: 2022-01-07 09:36
Go to main E-Print page  Using Flare-Induced Modulation of Three- and Five-Minute Oscillations for Studying Wave Propagation in the Solar Atmosphere  Multi-instrument STIX microflare study  Edit Entry  Download Preprint  Delete Entry 

Key
Go to main E-Print pageGo to main E-Print page.
Previous AbstractPrevious Abstract.
Next AbstractNext Abstract.
Download PreprintDownload Preprint.
Submitter's HomepageSubmitters Homepage.
Edit EntryEdit Entry.
View All Abstracts By SubmitterView all abstracts by submitter.
Delete AbstractDelete abstract.

Latest Entries
Structural evolution of a magnetic flux rope associated with a major flare in the solar active region 12205
Homologous Coronal Mass Ejections Caused by Recurring Formation and Disruption of Current Sheet within a Sheared Magnetic Arcade
Propagating Oscillations in the Lower Atmosphere Under Coronal Holes
Using Flare-Induced Modulation of Three- and Five-Minute Oscillations for Studying Wave Propagation in the Solar Atmosphere
Plasma dynamics in the flaring loop observed by RHESSI
Multi-instrument STIX microflare study
Disambiguation of Vector Magnetograms by Stereoscopic Observations from the Solar Orbiter/Polarimetric and Helioseismic Imager (PHI) and the Solar Dynamic Observatory (SDO)/Helioseismic and Magnetic Imager (HMI)
Enhanced Phase Mixing of Torsional Alfvén Waves in Stratified and Divergent Solar Coronal Structures, Paper II: Nonlinear Simulations
Multi-Passband Observations of A Solar Flare over the He I 10830 line
Multi-wavelength quasi-periodic pulsations in a stellar superflare
Probable detection of an eruptive filament from a superflare on a solar-type star
Global Energetics in Solar Flares. XIII. The Neupert Effect and Acceleration of Coronal Mass Ejections
Enhanced Phase Mixing of Torsional Alfvén Waves in Stratified and Divergent Solar Coronal Structures, Paper I: Linear Solutions
Variations of the Internal Asymmetries of Sunspot Groups During their Decay
Partial Eruption, Confinement, and Twist Buildup and Release of a Double-decker Filament
Overdense Threads in the Solar Corona Induced by Torsional Alfvén Waves
Implications of spicule activity on coronal loop heating and catastrophic cooling
The Magnetic Origin of Solar Campfires
On the evolution of a sub-C class flare: a showcase for the capabilities of the revamped Catania Solar Telescope
Direct evidence that twisted flux tube emergence creates solar active regions

Related Pages
MSU Solar Physics.
Max Millennium Science Mail Archive.
Max Millennium Message of the Day Mail Archive.
Max Millennium Flare Catalog

Archive Maintainer
Alisdair Davey



© 2000-2020 Solar Physics Group - Montana State University