Flare-Initiated Filament Oscillations.

Abstract

view Abstract Citations (9) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Flare-Initiated Filament Oscillations. Ramsey, Harry ; Smith, Sara F. Abstract A study was made of eleven abruptly disturbed filaments photographed at 10 sec intervals with a Ha 0.5 A Halle filter. The abrupt disturbance in each filament was initiated during the occurrence of a major flare at a separate location on the solar disk. Graphs were constructed showing the changes in visibility of each filament as a function of time. The filament visibility graphs of events observed only in the center of Ha were then compared to graphs of events in two wavelengths (center of Ha and Ha -0.5 A) and with events observed in three wavelengths (center of Ha, Ha -0.5 A, and Ha +0.5 A). All of the filaments studied exhibited an oscillating motion observed or interpreted as moving first to the red wing, Ha +0.5 A, and then to the blue wing, Ha -0.5 A. As many as four distinct complete oscillations were visible with decreasing amplitude and apparent constant frequency. The frequency of oscillation varied from one filament to another, and did not appear to relate to the size of the flare, the inferred velocity of the initiating disturbance from the flare, or the distance from the flare. The range of frequencies encountered was 1.5 to 10 complete cycles per hour (6 to 40 min for one complete oscillation). Each filament appeared to have its own characteristic frequency of oscillation, repeating this frequency with each subsequent disturbance. One filament, disturbed four times in a three-day period, oscillated with essentially the same frequency each time. Publication: The Astronomical Journal Pub Date: 1965 DOI: 10.1086/109569 Bibcode: 1965AJ.....70Q.688R full text sources ADS |