Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published May 15, 1988 | Published
Journal Article Open

Distribution functions for the time-averaged energies of stochastically excited solar p-modes

Abstract

We study the excitation of a damped harmonic oscillator by a random force as a model for the stochastic excitation of a solar p-mode by turbulent convection. An extended sequence of observations is required to separate different p-modes and thus determine the energies of individual modes. Therefore, the observations yield time-averaged values of the energy. We apply the theory of random differential equations to calculate distribution functions for the time-averaged energy of the oscillator. The instantaneous energy satisfies a Boltzmann distribution. With increasing averaging time the distribution function narrows, and its peak shifts toward the mean energy. We also perform numerical integrations to generate finite sequences of time-averaged energies. These are treated as simulated data from which we obtain approximate probability distributions for the time-averaged energy. A comparison of our calculated distributions with those determined observationally should help to resolve whether the solar p-modes are stochastically excited. If they are, modes of the same frequency with degree l ≾ 200 should have identical values for the products of their mean energies, line-widths, and masses. If, in addition, turbulence or radiative dissipation provides the principal damping mechanism, the mean energies should be independent of angular order, l.

Additional Information

© 1988 American Astronomical Society. Received 1987 August 12; accepted 1987 November 9. P. K. is grateful to Ken Libbrecht for many useful discussions. The research reported in this paper was supported by NSF through grant AST-861299

Attached Files

Published - 1988ApJ___328__879K.pdf

Files

1988ApJ___328__879K.pdf
Files (816.9 kB)
Name Size Download all
md5:bfbe7a99918b84e9700631bd7dede3db
816.9 kB Preview Download

Additional details

Created:
August 22, 2023
Modified:
October 23, 2023