Implications of solar p-mode frequency shifts

Journal Article · Mon Apr 01 04:00:00 EST 1991 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/169858· OSTI ID:5544306

Goldreich, P

An expression is derived that relates solar p-mode frequency shifts to changes in the entropy and magnetic field of the sun. The frequency variations result from changes in path length and propagation speed. Path length changes dominate for entropy perturbations, and propagation speed changes dominate for most types of magnetic field peturbations. The p-mode frequencies increased along with solar activity between 1986 and 1989; these frequency shifts exhibited a rapid rise with increasing frequency followed by a precipitous drop. The positive component of the shifts can be accounted for by variations of the mean square magnetic field strength in the vicinity of the photosphere. The magnetic stress perturbation decays above the top of the convection zone on a length scale comparable to the pressure scale height and grows gradually with depth below. The presence of a resonance in the chromospheric cavity means that the transition layer maintains enough coherence to partially reflect acoustic waves even near cycle maximum. 25 refs.

• Research Organization: California Inst. of Tech., Pasadena, CA (USA)
• OSTI ID: 5544306
• Journal Information: Astrophysical Journal; (USA), Journal Name: Astrophysical Journal; (USA) Vol. 370; ISSN ASJOA; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATMOSPHERES
BRIGHTNESS
CHROMOSPHERE
DISTURBANCES
ENTROPY
FLUID MECHANICS
HYDRODYNAMICS
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
MAIN SEQUENCE STARS
MECHANICS
OPTICAL PROPERTIES
OSCILLATION MODES
OSCILLATIONS
PHYSICAL PROPERTIES
SOLAR ACTIVITY
SOLAR ATMOSPHERE
SOUND WAVES
STARS
SUN
THERMODYNAMIC PROPERTIES
WAVE PROPAGATION