E-Print Archive

There are 4236 abstracts currently viewable.


Advanced Search
Main Page Add New E-Print Submitter
News Help/FAQ About Preferences
Manage Key Phrase
* News 04/04/20 * The archive is using a new backend database. This has thrown up a few SQL errors in the last few days. If you have any issues please email adavey@nso.edu with either the number of eprint you are trying to edit or a link to your preprint.

The Multi-instrument (EVE-RHESSI) DEM for Solar Flares, and Implications for Nonthermal Emission View all abstracts by submitter

Amir Caspi   Submitted: 2019-08-26 12:53

Solar flare X-ray spectra are typically dominated by thermal bremsstrahlung emission in the soft X-ray (<~10 keV) energy range; for hard X-ray energies (≳30 keV), emission is typically nonthermal from beams of electrons. The low-energy extent of nonthermal emission has only been loosely quantified. It has been difficult to obtain a lower limit for a possible nonthermal cutoff energy due to the significantly dominant thermal emission. Here we use solar flare data from the extreme ultraviolet Variability Experiment on board the Solar Dynamics Observatory and X-ray data from the Reuven Ramaty High Energy Spectroscopic Imager to calculate the Differential Emission Measure (DEM). This improvement over the isothermal approximation and any single-instrument DEM helps to resolve ambiguities in the range where thermal and nonthermal emission overlap, and to provide constraints on the low-energy cutoff. In the model, thermal emission is from a DEM that is parameterized as multiple Gaussians in Log(T). Nonthermal emission results from a photon spectrum obtained using a thick-target emission model. Spectra for both instruments are fit simultaneously in a self-consistent manner. Our results have been obtained using a sample of 52 large (Geostationary Operational Environmental Satellite X- and M-class) solar flares observed between 2011 and 2013. It turns out that it is often possible to determine low-energy cutoffs early (in the first two minutes) during large flares. Cutoff energies at these times are typically low, less than 10 keV, when assuming coronal abundances. With photospheric abundances, cutoff energies are typically ∼10 keV higher, in the ∼17-25 keV range.

Authors: James M. McTiernan, Amir Caspi, Harry P. Warren
Projects: GOES X-rays,RHESSI,SDO-EVE

Publication Status: Published -- McTiernan, J. M., Caspi, A., & Warren, H. P. 2019, ApJ, 881, 161; DOI 10.3847/1538-4357/ab2fcc
Last Modified: 2019-08-27 10:10
Go to main E-Print page  MinXSS-1 CubeSat On-Orbit Pointing and Power Performance: The First Flight of the Blue Canyon Technologies XACT 3-axis Attitude Determination and Control System  A Statistical Study of Solar Filament Eruptions That Forms High-Speed Coronal Mass Ejections  Edit Entry  Download Preprint  Delete Entry 

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
Sunquake with a second-bounce, other sunquakes and emission associated with X9.3 flare of 6 September 2017. II. Proposed interpretation
f-mode strengthening from a localized bipolar subsurface magnetic field
Imaging and spectral study on the null point of a fan-spine structure during a solar flare
Forecasting Solar Cycle 25 Using Deep Neural Networks
An Observational Test of Solar Plasma Heating by Magnetic Flux Cancellation
The Drivers of Active Region Outflows into the Slow Solar Wind
HXR emission from an activated flux rope and subsequent evolution of an eruptive long duration solar flare
A Survey of Computational Tools in Solar Physics
Sunquake with a second bounce, other sunquakes, and emission associated with the X9.3 flare of 6 September 2017. I. Observations
The PDFI_SS Electric Field Inversion Software
Spatial Distribution of Origin of Umbral Waves in a Sunspot Umbra
A Unique Resource for Solar Flare Diagnostic Studies: the SMM Bent Crystal Spectrometer
Inferring Vector Magnetic Fields from Stokes Profiles of GST/NIRIS Using a Convolutional Neural Network
Global Energetics of Solar Flares, X. Petschek Reconnection Rate and Alfvén Mach Number of Magnetic Reconnection Outflows
Transverse coronal loop oscillations excited by homologous circular-ribbon flares
Temporal evolution of oscillating coronal loops
Intrusion of Magnetic Peninsula toward the Neighboring Opposite-polarity Region That Triggers the Largest Solar Flare in Solar Cycle 24
On the Relationship Between Transit Time of ICMEs and Strength of the Initiated Geomagnetic Storms
Standing kink waves in sigmoid solar coronal loops: implications for coronal seismology
Excitation of negative energy surface magnetohydrodynamic waves in an incompressible cylindrical plasma

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