Energy distribution of solar oscillation modes inferred from space-based measurements

Document Type

Article

Publication Date

2-10-2001

Abstract

We have measured the energy distribution of solar p- and f-mode oscillations of angular degree and temporal frequency in the range 100 < l < 800 and 2 < v(mHz) < 4 using helioseismology data from the Solar Oscillations Investigation-Michelson Doppler Imager instrument on the Solar and Heliospheric Observatory satellite. At temporal frequency v ≈ 3 mHz, the surface velocity power per oscillation mode increases slightly with angular degree between l = 100 and l = 200 but decreases rather steeply with l above l = 200, in approximate agreement with earlier findings from ground-based measurements. From this we infer that the time-averaged energy per mode, which is theoretically related to the modal surface velocity power, decreases steeply with l, at fixed frequency, over the entire observed l-range. Specifically, at v = 3.1 mHz, the energy per mode drops by a factor of ≈10 between l = 150 and l = 650, a circumstance not quantitatively understood at present.

Identifier

0035835519 (Scopus)

Publication Title

Astrophysical Journal

External Full Text Location

https://doi.org/10.1086/318935

e-ISSN

15384357

ISSN

0004637X

First Page

L103

Last Page

L106

Issue

1 PART 2

Volume

548

Grant

NAS5-3077

Fund Ref

National Aeronautics and Space Administration

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