E-Print Archive

There are 4099 abstracts currently viewable.


Advanced Search
Main Page Add New E-Print Submitter
News Help/FAQ About Preferences
Manage Key Phrase
Temporal and Spatial Analyses of Spectral Indices of Nonthermal Emissions Derived from Hard X-Rays and Microwaves View all abstracts by submitter

Ayumi Asai   Submitted: 2012-12-10 18:28

We studied electron spectral indices of nonthermal emissions seen in hard X-rays (HXRs) and in microwaves. We analyzed 12 flares observed by the Hard X-ray Telescope aboard {it Yohkoh}, Nobeyama Radio Polarimeters (NoRP), and the Nobeyama Radioheliograph (NoRH), and compared the spectral indices derived from total fluxes of hard X-rays and microwaves. Except for four events, which have very soft HXR spectra suffering from the thermal component, these flares show a gap Deltadelta between the electron spectral indices derived from hard X-rays deltaX and those from microwaves deltamu (Deltadelta = deltaX - deltamu) of about 1.6. Furthermore, from the start to the peak times of the HXR bursts, the time profiles of the HXR spectral index deltaX evolve synchronously with those of the microwave spectral index deltamu, keeping the constant gap. We also examined the spatially resolved distribution of the microwave spectral index by using NoRH data. The microwave spectral index deltamu tends to be larger, which means a softer spectrum, at HXR footpoint sources with stronger magnetic field than that at the loop tops. These results suggest that the electron spectra are bent at around several hundreds of keV, and become harder at the higher energy range that contributes the microwave gyrosynchrotron emission.

Authors: Ayumi Asai, Junko Kiyohara, Hiroyuki Takasaki, Noriyuki Narukage, Takaaki Yokoyama, Satoshi Masuda, Masumi Shimojo, and Hiroshi Nakajima
Projects: Nobeyama Radioheliograph,Yohkoh-HXT,Yohkoh-WBS

Publication Status: ApJ (accepted)
Last Modified: 2012-12-10 18:39
Go to main E-Print page  Stereoscopic Analysis of the 31 August 2007 Prominence Eruption and Coronal Mass Ejection  Origins of Rolling, Twisting and Non-Radial Propagation of Eruptive Solar Events  Edit Entry  Download Preprint  Submitter's Homepage 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
On the Origin of Solar Torsional Oscillations and Extended Solar Cycle
What Sets the Magnetic Field Strength and Cycle Period in Solar-type Stars?
Stereoscopic Observations of an Erupting Mini-filament Driven Two-Sided-Loop Jet and the Applications for Diagnosing Filament Magnetic field
Dynamic Processes of the Moreton Wave on 2014 March 29
Shock Heating Energy of Umbral Flashes Measured with Integral Field Unit Spectroscopy
Stealth Coronal Mass Ejections from Active Regions
Coronal Loop Scaling Laws for Various Forms of Parallel Heat Conduction
Structure of the transition region and the low corona from TRACE and SDO observations near the limb
Quantifying the relationship between Moreton-Ramsey waves and "EIT waves" using observations of 4 homologous wave events
Formation of quasi-periodic slow magnetoacoustic wave trains by the heating/cooling misbalance
Fundamental Transverse Vibrations of the Active Region Solar Corona
Damping of slow magnetoacoustic oscillations by the misbalance between heating and cooling processes in the solar corona
Magnetic helicity and eruptivity in active region 12673
Impulsive coronal heating from large-scale magnetic rearrangements: from IRIS to SDO/AIA
Probing the effect of cadence on the estimates of photospheric energy and helicity injections in eruptive active region NOAA AR 11158
The birth of a coronal mass ejection
Oscillations of the baseline of solar magnetic field and solar irradiance on a millennial timescale
Chromospheric cannonballs on the Sun
Magnetic Helicity from Multipolar Regions on the Solar Surface
Exoplanet predictions based on harmonic orbit resonances

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

© 2003 Solar Physics Group - Montana State University