Solar cycle variability of high-frequency and high-degree p-mode oscillation frequencies

Most studies of the solar cycle dependence of the frequencies of the p-mode oscillations have employed only the low- and intermediate-degree modes having nu less than or equal to 4500 muHz. Most of these past studies have also employed lengthy observing runs covering two or more solar rotations. In this paper we will present measurements of the frequencies of both the high-nu and high-l oscillations which we have obtained at widely-varying levels of solar activity over the past 13 years. In contrast to the case of the lower-nu p-modes, the frequencies of the higher-nu modes are anti-correlated with solar activity. Furthermore, these frequencies can be estimated reliably from runs which are as short as only a few days. Using such brief time series, we have been able to obtain frequencies which show a higher sensitivity to changing levels of activity than has been the case in the past. This higher sensitivity gives us the expectation that such frequency shifts will provide tighter constraints upon future estimates of their origin.