Rhessi microflare statistics
This presentation is the property of its rightful owner.
Sponsored Links
1 / 15

RHESSI Microflare Statistics PowerPoint PPT Presentation


  • 84 Views
  • Uploaded on
  • Presentation posted in: General

RHESSI Microflare Statistics. Steven Christe 1,2 , Iain Hannah 2 , Säm Krucker 2 , J. McTiernan 2 , R. P. Lin 1,2 1 Physics Department, University of California at Berkeley 2 Space Sciences Lab, University of California at Berkeley. Past Work. HXR Slope : 1.5-1.7 SXR Slope : 1.7

Download Presentation

RHESSI Microflare Statistics

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Rhessi microflare statistics

RHESSI Microflare Statistics

Steven Christe1,2, Iain Hannah2, Säm Krucker2,

J. McTiernan2, R. P. Lin1,2

1Physics Department, University of California at Berkeley

2Space Sciences Lab, University of California at Berkeley


Past work

Past Work

  • HXR Slope : 1.5-1.7

  • SXR Slope : 1.7

  • EUV Slope : 1.7-2.5

  • Magic Slope : 2


Enter rhessi

Enter RHESSI

  • Provides unique sensitivity in the 3-15 keV energy range.

  • Effective area ~100 times larger than HXIS (SMM) at 10 keV.

  • Spectral resolution 1 keV.

  • Imaging down to 2 arcseconds.


The flare list

The Flare List

  • Created using the standard, time-tested, flare finding algorithm (by J. McTiernan) applied to the 6-12 keV channel.

  • Time period : Jan - Jun 2004

  • Number of Flares : 8500 analyzed (1500)

  • Flare Frequency : 2 per hour

  • Flare sizes : A1 < GOES CLASS < C1


The flare list1

The Flare List


Flare statistics

Flare Statistics

  • Min. Peak count rate - ~100/s (GOES CLASS A1)

  • Average Duration : ~ 2 minutes (4 s. resolution)


Spectral fitting ospex

Spectral Fitting - OSPEX

Light curve

Photon Spectrum


Auto flare spectra ospex

Auto Flare Spectra - OSPEX

  • Created spectrum files for all times during the time period considered.

  • Night-time backgrounds were chosen for each flare.

  • Flares were split into 16 s intervals and fit automatically with a thermal continuum and a broken power law.

  • The total (thick target) nonthermal power is calculated for each interval and added to get the total nonthermal energy.


Parameter distributions

Parameter Distributions

• Average Temperature :

10 MK (detector limited)

• Average Gamma : 5-7

• Broad Range of break

of energies with some

bias to 10 keV.

NOTE : Red lines represent an imposed cutoff.


Energy distribution

Energy Distribution


Region of validity

Region of Validity

  • Large flares (~105 peak count rate) are excluded.

  • Flares with less than ~100 peak count rate were not easily imaged.

  • Trusted energy range ~ 1029- 1030 erg.


Past work1

Past Work

  • HXR Slope : 1.5-1.7

  • SXR Slope : 1.7

  • EUV Slope : 1.7-2.5

  • Magic Slope : 2

• RHESSI Slope : ~1.4

in 1029-1030 erg range.


Some questions marks

Some Questions Marks

Instrument

sensitivity?

???


Conclusions

Conclusions

  • A typical microflare :

    • last a ~2 minutes

    • Temperature of 10 MK

    • Power law index ~ 6

    • Low Energy Cutoff ~ 7-10 keV

    • Total Energy ~ 1029 erg

  • Down to 1029 erg,

    • the energy contained in microflares seems insufficient to heat the Corona.

    • There is no evidence of a break to a steeper slope.


  • Login