Characteristics of Magnetohydrodynamic Oscillations Observed with Michelson Doppler Imager

Astronomy and Astrophysics – Astrophysics

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

4 Pages, 4 Figures -- For better Figure files see: http://www.astro.ucla.edu/~norton/pub_list.html

Scientific paper

10.1086/312072

We report on the spatial distribution of magnetogram oscillatory power and phase angles between velocity and magnetogram signals as observed with the Michelson Doppler Imager. The dataset is 151.25 arcsec times 151.25 arcsec containing sunspot from Dec 2, 1997 with a temporal sampling interval of 60 seconds and spatial sampling of 0.605 arcsec. Simultaneously observed continuum intensity and surface velocity accompany the magnetic information. We focus on three frequency regimes: 0.5-1.0, 3.0-3.5 and 5.5-6.0 mHz corresponding roughly to timescales of magnetic evolution, p-modes and the 3 minute resonant sunspot oscillation. Significant low frequency magnetogram power is found in lower flux pixels, 100-300 Gauss, in a striking ring with filamentary structure surrounding sunspot. Five minute magnetogram power peaks in extended regions of flux 600-800 Gauss. The 3 minute oscillation is observed in sunspot umbra in pixels whose flux measures 1300-1500 Gauss. Phase angles of approximately -90 degrees between velocity and magnetic flux in the 3.0-3.5 and 5.5-6.0 mHz regimes are found in regions of significant cross amplitude.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

Characteristics of Magnetohydrodynamic Oscillations Observed with Michelson Doppler Imager does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Characteristics of Magnetohydrodynamic Oscillations Observed with Michelson Doppler Imager, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Characteristics of Magnetohydrodynamic Oscillations Observed with Michelson Doppler Imager will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-438682

All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.