1 / 20

Coronal magnetic field observations

Coronal magnetic field observations. Useful coronal field model constraints can be obtained from IR observations This is a vigorous activity, with three serious ongoing efforts (plus important solar radio measurements proposed). J.R. Kuhn, R. Coulter, H. Lin, D. Mickey. Are images enough?.

hamlin
Download Presentation

Coronal magnetic field observations

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. Coronal magnetic field observations • Useful coronal field model constraints can be obtained from IR observations • This is a vigorous activity, with three serious ongoing efforts (plus important solar radio measurements proposed) J.R. Kuhn, R. Coulter, H. Lin, D. Mickey

  2. Are images enough? (from Chen et al., Low, Gibson, Roussev et al.)

  3. Magnetic linear polarization sensitivity B Q+U Q E

  4. Coronal Hanle measurements • Raouafi, Sahal-Bréchot, Lemaire, A&A 396, 1019, 2002. • OVI 103.2nm polarization measurement using CDS in a coronal hole (9%, 9 degree from limb tangent) • Analysis: non-unique solution requires both B of a “few gauss” and velocity of “few 10’s km/s”

  5. QU forbidden line observations • Habbal, Woo, Arnaud, Ap.J. 558, 825, 2001 • FeXIII HAO/NSO KELP project 1980’s

  6. Coronal forbidden line Zeeman Observations • Lin, Penn, Tomczyk, ApJ, 541, L83 (2000) • FeXIII V polarimetry

  7. Why IR: Atmospheric backgrounds

  8. IR expectations • Judge, Casini, Tomczyk, Burkepile... (http://comp.hao.ucar.edu/how.html)

  9. The IR corona Kuhn et al. 1995, 1999 Also Judge et al., 2002

  10. Ideal B measurement sensitivity 5 min observation, 10” pixel

  11. Ongoing Coronal B efforts • COMP, Ground-Based Coronal Research Project (HAO lead) • ATST (NSO) • SOLARC (IfA)

  12. SOLARCRoy Coulter, Jeff Kuhn, Haosheng Lin, Don Mickey 3.93 micron 100nm spectrograph filter bandpass

  13. Magnetic field measurements... • ...will be achieved in the quiet corona with a sensitivity of better than 1 G • ...from IR coronal observations obtained by several research groups using sensitive polarimetry techniques • ...on a timescale of one year

  14. Vector Inversions • FF and potential model from Low (1993) • External potential field+FF at r<R + dipole • Radon transform using Algebraic Reconstruction Technique z y Q s

  15. The projection problem

  16. The inversion 10 iterations over 12 projections spaced 15 degrees...

  17. Another inversion 6 projections, 0-90 degrees...

  18. Potential field...

  19. Long Wavelengths Prime or Gregorian Focus SOLARC Fast 1-5mu IR Camera chop Warm IR Spectrograph Cold Narrow-band filter

More Related