Abstract We derive phase differences between irradiance and full-disk velocity variations for l=0, 1, and 2 modes with order ranging from 11 up to 30 (1.8–4.3mHz). We use irradiance measurements from the IPHIR instrument flown on the PHOBOS mission to Mars during the second half of 1988, and simultaneous velocity measurements obtained at Tenerife. The IPHIR instrument measures broad-band irradiance fluctuations and the derived phase differences are therefore typical of the deep layers of the photosphere. We select three one week intervals from the 155 day observing interval of PHOBOS 2 for which simultaneous good quality velocity data are available. We find a smooth variation of the phase difference between irradiance at 500nm (5nm FWHM) and velocity from about 70° at 1.8mHz to 145° at 2.5mHz, while it remains roughly constant at 145° degrees up to at least 3.5mHz, and possibly up to 4.3mHz. We also show that the phase differences between the green (500nm) and red (865nm) channels does not differ significantly from zero below 3mHz, while a small difference of about 10° may exist at higher frequencies.


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    Title :

    Phase difference between irradiance and velocity in low degree solar p-modes


    Contributors:

    Published in:

    Publication date :

    1991-01-01


    Size :

    4 pages




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English



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