MHD Oscillations Observed in the Solar Photosphere with the Michelson Doppler Imager

1998 ◽  
pp. 453-454 ◽  
Author(s):  
A. A. Norton ◽  
R. K. Ulrich ◽  
R. S. Bogart ◽  
R. I. Bush ◽  
J. T. Hoeksema
Keyword(s):  
Solar Photosphere ◽  
Michelson Doppler Imager ◽  
Doppler Imager

scholarly journals MHD Oscillations Observed in the Solar Photosphere with the Michelson Doppler Imager

1998 ◽  
Vol 185 ◽  
pp. 453-454 ◽  
Author(s):  
A.A. Norton ◽  
R. K. Ulrich ◽  
R.S. Bogart ◽  
R.I. Bush ◽  
J.T. Hoeksema
Keyword(s):  
Solar Atmosphere ◽  
Acoustic Waves ◽  
Mhd Waves ◽  
Solar Photosphere ◽  
Michelson Doppler Imager ◽  
Doppler Imager

Magnetohydrodynamic (MHD) oscillations are observed in the solar photosphere with the Michelson Doppler Imager (MDI). The absorption of acoustic waves by sunspots (Braun et al., 1988) and the possible conversion of acoustic waves into MHD waves (Spruit et al., 1992) provide a plausible basis for the existence of MHD waves in the solar atmosphere and motivate this attempt at observation.

scholarly journals Photospheric high-frequency acoustic power excess in sunspot umbra: signature of magneto-acoustic modes

2013 ◽  
Vol 31 (8) ◽  
pp. 1357-1364 ◽  
Author(s):  
S. Zharkov ◽  
S. Shelyag ◽  
V. Fedun ◽  
R. Erdélyi ◽  
M. J. Thompson
Keyword(s):  
Magnetic Field ◽  
Acoustic Waves ◽  
High Frequency ◽  
Acoustic Power ◽  
Solar Photosphere ◽  
Heliospheric Observatory ◽  
Magnetohydrodynamic Waves ◽  
Sunspot Umbra ◽  
Doppler Imager ◽  
Power Enhancement

Abstract. We present observational evidence for the presence of MHD (magnetohydrodynamic) waves in the solar photosphere deduced from SOHO/MDI (Solar and Heliospheric Observatory/Michelson Doppler Imager) Dopplergram velocity observations. The magneto-acoustic perturbations are observed as acoustic power enhancement in the sunspot umbra at high-frequency bands in the velocity component perpendicular to the magnetic field. We use numerical modelling of wave propagation through localised non-uniform magnetic field concentration along with the same filtering procedure as applied to the observations to identify the observed waves. Guided by the results of the numerical simulations we classify the observed oscillations as magneto-acoustic waves excited by the trapped sub-photospheric acoustic waves. We consider the potential application of the presented method as a diagnostic tool for magnetohelioseismology.

Results from proton damage tests on the Michelson Doppler Imager CCD for SOHO

1993 ◽  
Author(s):  
Igor Zayer ◽  
Ira Chapman ◽  
Dexter W. Duncan ◽  
G. A. Kelly ◽  
Keith E. Mitchell
Keyword(s):  
Michelson Doppler Imager ◽  
Doppler Imager
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