February 20, 2015
Major and Classification
- Edward Rhodes, Ph.D.
Temporal Dependence of the Solar P-Mode Oscillation Frequencies to Changes in Solar Activity
Previous studies using the so-called “ring diagram” method of local helioseismology have shown that the sensitivity of the solar p-mode oscillation frequencies to changes in solar activity may change as a function of time as the solar cycle progresses from one minimum to the following maximum. However, the ring diagram method only analyzes small portions of the sun and therefore the results obtained with that method may be unreliable. This paper presents the results of using the methods of global helioseismology rather than the ring diagram method to study the temporal dependence of the sensitivity of the solar p-mode oscillation frequencies to changes in solar activity. In this study, time series of full-disk GONG Dopplergrams are used, and the power spectra of these Dopplergrams are computed using an existing software program. The power spectra are then fit with a program which computes the frequencies, widths, and amplitudes of the p-mode peaks contained within them. The resulting tables of frequencies are then compared using a program which does numerical subtraction on a mode-by-mode basis. Finally, a linear regression is used in order to analyze the sensitivity of the solar p-mode oscillation frequencies to changes in solar activity. Helioseismology is a significant area of research because it enables solar astronomers to probe the sun’s interior where the nuclear reaction which power the sun and drive its evolution take place.