Solar Physics (2006) DOI: 10.1007/s11207-006-0234-y C  Springer 2006 POSSIBILITY OF EXCITATION OF LOW-ℓ P-MODES BY ENERGETIC SOLAR TRANSIENTS ASHOK AMBASTHA Udaipur Solar Observatory, Physical Research Laboratory, P. O. Box 198, Udaipur 313001, India (e-mail: ambastha@prl.res.in) and H.M. ANTIA Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India (e-mail: antia@tifr.res.in) (Received 5 June 2006; accepted 26 September 2006) Abstract. We examine the temporal variation of power in low-ℓ modes using GONG data for the period of May 1995 – October 2005 and compare this with disk-integrated flare and CME indices. A poor correlation between the running means of Flare Index and mode power is found. A similar result is found for CME Index also. Variations in the running mean mode power corresponding to ℓ = 0 modes with different radial orders are generally stochastic in nature. This behaviour is also reflected in the distribution of mode power. 1. Introduction The power of solar p-modes has been found to vary on temporal scales of days to several weeks (Chaplin et al., 1995, 1997; Gavryusev and Gavryuseva, 1997). These variations are generally explained to result from interference between the mode excitations (Goldreich, Murray, and Kumar, 1994) that are expected from stochastic excitation of modes. However, Chaplin et al. (1997) found excess of excitation events at the highest powers in comparison with the model. They used low-ℓ p-mode data from BiSON to derive the distribution of the observed strengths of the solar oscillations. They demonstrated that some features at very high powers represent departure from the exponential distribution, which are not explained by stochastically forced, damped harmonic oscillator model. The existence of high- power events in the p-mode data, if indeed found to be significant, raises the question of their origin that needs to be addressed. A significant anti-correlation between the total power of low degree p-modes and the mean solar magnetic field was found by Elsworth et al. (1993), Gavryusev and Gavryuseva (1996, 1997) and Howe et al. (2003). Similar results were found for higher degree modes from GONG data (Komm, Howe, and Hill, 2000). Gavryusev and Gavryuseva (1999) used a 1010-day long disk-integrated time-series obtained by GONG during June 1995 – March 1998, i.e. in the period around the solar minimum, to study the temporal behaviour of low-degree p-mode power. Presence