E-Print Archive

There are 4172 abstracts currently viewable.


Advanced Search
Main Page Add New E-Print Submitter
News Help/FAQ About Preferences
Manage Key Phrase
Solar Cycle Variation of Coronal Temperature, Emission Measure, and Soft X-ray Irradiance Observed with Yohkoh Soft X-ray Telescope View all abstracts by submitter

Aki Takeda   Submitted: 2019-12-03 20:28

This paper presents the solar soft X-ray irradiance(0.3-3.0nm) obtained from the mission-long full-Sun X-ray images observed with the Soft X-ray Telescope(SXT) of the Yohkoh mission(1991-2001). The irradiance was calculated using filter-ratio temperatures and emission measures from the full-Sun integrated X-ray signals employing a coronal spectrum synthesized with CHIANTI atomic database version 8.0. Dependence of the results on the assumption of elemental abundances is investigated. The SXT irradiance for a shorter wavelength range was also calculated and compared with the low energy flux(0.1-0.8nm) of the X-Ray Sensor(XRS) aboard the GOES satellite. To incorporate the spatial information of the observed corona, we tried the alternative method to derive irradiance by applying the filter ratio method to the images of Northern hemispheric corona instead of spatially integrated signals from there. The emission-measure weighted average of the spatially resolved temperatures turned out to be generally 20 to 30% lower than those derived from the integrated signals, while the total of spatially resolved emission measures are accordingly 1.5 to 2 times higher. This trend is enhanced when solar activity is the lowest in early 1996. The irradiance obtained from the alternative method does not significantly vary from the result from the integrated signals. This provides some validation for the simpler full-Sun integrated method. The temporal variation of the emission measures of cool(<1.5MK), medium and hot(>2.5MK) components indicates that the ratio of the hot component relative to the medium component is higher in the ascending phase(mid 1998-2001) than the descending phase(1992-1995) of the solar activity cycle.

Authors: Aki Takeda, Loren Acton, and Nicole Albanese
Projects: Yohkoh-SXT

Publication Status: Accepted in the ApJ
Last Modified: 2019-12-04 11:30
Go to main E-Print page  The Effect of Anisotropic Viscosity on the Nonlinear Kink Instability  Magnetic Rayleigh-Taylor Instability at a Contact Discontinuity With   Oblique Magnetic Field  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
The Distribution of Time Delays Between Nanoflares in Magnetohydrodynamic Simulations
Data-driven MHD Simulation of the Formation and Initiation of a Large-scale Pre-flare Magnetic Flux Rope in Solar Active Region 12371
NVST observations of collision-induced apparent fan-shaped jets
Cosmic ray interactions in the solar atmosphere
A correlation in the waiting-time distributions of solar flares
Alternative Models of Zebra Patterns in the Event on June 21, 2011
Torsional slow-mode oscillations discovered in the magnetic free energy during solar flares
Particle acceleration in coalescent and squashed magnetic islands II. Particle-In-cell approach
The time step constraint in radiation hydrodynamics
Continuous Null-Point Magnetic Reconnection Builds Up a Torus Unstable Magnetic Flux Rope Triggering the X9.3 Flare in Solar Active Region~12673
A Comparison of Flare Forecasting Methods. IV. Evaluating Consecutive-Day Forecasting Patterns
The New 2018 Version of the Meudon Spectroheliograph
Longitudinal filament oscillations enhanced by two C-class flares
Spatio-temporal energy partitioning in a non-thermally dominated two-loop solar flare
Meteospace, a New Instrument for Solar Survey at the Calern Observatory
Correcting the effect of magnetic tongues on the tilt angle of bipolar active regions
Hi-C 2.1 Observations of Jetlet-like Events at Edges of Solar Magnetic Network Lanes
Fine-scale Explosive Energy Release at Sites of Prospective Magnetic Flux Cancellation in the Core of the Solar Active Region Observed by Hi-C 2.1, IRIS, and SDO
Remote coronal dimmings related to a circular-ribbon flare
Formation and Eruption of a Mini-sigmoid Originating in Coronal Hole

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