1 / 16

RHESSI Investigations of the Neupert Effect in Solar Flares

Investigating the Neupert Effect in solar flares using RHESSI observations of soft and hard X-ray emissions, revealing the relationship between accelerated electrons and plasma heating. Limitations of RHESSI and comparison with GOES data are discussed.

danas
Download Presentation

RHESSI Investigations of the Neupert Effect in Solar Flares

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. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. RHESSI Investigations of the Neupert Effect in Solar Flares Brian R. Dennis AAS/SPD Meeting 6 June 2002

  2. The Neupert Effect • The time integral of the hard X-ray emission closely matches the temporal variation of the soft X-ray emission. • Implies that accelerated electrons that produce the hard X-rays also heat the plasma that produces the soft X-rays.

  3. SXR:HXR Ratio vs. Flare SizeA. Veronig et al. A&A, in press (2002)

  4. RHESSI Contribution • RHESSI observes both the soft X-rays (down to ~3 keV) and the hard X-rays with the same detectors. • RHESSI also provides 2 arcsecond imaging capability in both soft and hard X-rays. • RHESSI’s temporal resolution for images is 2 s for a complete set of spatial Fourier components. • The spatially integrated time resolution is limited only by counting statistics.

  5. RHESSI’s Limitations • Suffers pulse pile up when the rates exceed ~10,000 counts per detector per second. • Shutters moved into FOV when dead time reaches ~10%. Limits lower energy response below ~10 keV. • K-escape photons contaminate low energy counts with higher energy emission.

  6. RHESSI/GOES Comparison

  7. RHESSI Light Curves 6 – 12 keV 12 – 25 keV 25 – 50 keV 50 – 100 keV 10 April 2002 GOES 10 1 - 8 Å Time derivative GOES 1 - 8 Å

  8. RHESSI Images 10 April 200219:02:34 – 19:03:03 UT 6 – 12 keV 12 – 25 keV 50 – 100 keV 25 - 50 keV

  9. X1.5 Flare on 21 April 20022650 + 0043 0151 0238 GO8 5 XRA 1-8A X1.5 6.0E-01 9906

  10. X1.5 Flare on 21 April 2002

  11. RHESSI Light Curves 25 – 50 keV 50 – 100 keV 21 April 2002 GOES 1 - 8 Å Time derivative GOES 1 - 8 Å

  12. X1.5 Flare on 21 April 2002

  13. Start of X1.5 Flare on 21 April 2002TRACE images at 195 Å, RHESSI 12 – 25 keV contours 00:42:50 – 00:43:10 UT 00:48:54 – 00:49:14 UT

  14. Start of X1.5 Flare on 21 April 2002TRACE images at 195 Å, RHESSI 12 – 25 keV contours

  15. X1.5 Flare on 21 April 2002TRACE 195Å images and RHESSI contours at times of hard X-ray peaks 12-25 keV 50 – 100 keV 01:15:43 – 01:16:03 UT 01:23:27 – 01:23:47 UT

  16. Conclusions • Neupert Effect is alive and well. • Fraction of flare energy in accelerated electrons • Increases with flare size on average • Decreases with time during 21 April X flare • Additional heating mechanism is required

More Related