Coronal oscillations

Journal Article · Sun Apr 15 04:00:00 EST 1984 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/161956· OSTI ID:6590433

Roberts, B; Edwin, P M; Benz, A O

Magnetoacoustic oscillations in a solar coronal inhomogenity (e.g., coronal loop) are shown to take place with two distinct periodicities, one on an acoustic (long) time scale. and the other on an Alfvenic (short) time scale and the other on an Alfenic (short) time scale. The short period modes-fast magnetoacoustic waves-are trapped in regions of low Alfen speed: typically, this corresponds to high density loops or dense open field regions. Their periods may be on the order of seconds. We discuss the form of the fast oscillations for both standing modes in a closed loop and impulsively generated disturbances in a loop or open field structure. Impulsively generated waves in density enhancement exhibit both periodic and quasi-periodic phases. Symmetric oscillations (sausage modes) are analogous to Pekeris waves in oceanography; asymmetrical (kink) disturbances are skin to Love waves in seismology. It is suggested that fast magnetoacoustic waves may explain the observed pulsations in Type IV radio events, the sausage waves providing the desired 1 s periodicites.

• Research Organization: Department of Applied Mathematics, University of St. Andrews, Scotland
• OSTI ID: 6590433
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 279:2; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATMOSPHERES
FAST MAGNETOACOUSTIC WAVES
FLUID MECHANICS
HYDRODYNAMICS
HYDROMAGNETIC WAVES
MAGNETIC FIELD CONFIGURATIONS
MAGNETIC FIELDS
MAGNETOACOUSTIC WAVES
MAGNETOHYDRODYNAMICS
MECHANICS
OSCILLATION MODES
SOLAR CORONA
STELLAR ATMOSPHERES
STELLAR CORONAE
WAVE PROPAGATION