ULF waves in the solar wind, their coupling to the magnetosphere and associated higher-frequency pulsations.

Recent work has shown the existence at geosynchronous orbit of wave power at frequencies substantially below that of fundamental field-line resonances. The existence of spectral power below that of fundamental frequencies indicates that the driver must be external to the magnetosphere, i.e, that the source is contained in the solar wind. Other work has shown that frequencies matching field-line resonances can sometimes also be observed in the solar wind. The combined spectrum that includes power at fundamental frequencies and lower maps precisely to p-mode helioseismic spectra and the question has been raised whether these helioseismic modes may stimulate the magnetospheric fluctuations. Coherences have been calculated between the magnetometers on {ACE} and Ulysses (in the solar wind) and {GOES-10} (within the magnetosphere), and show several frequencies where nine coherences are significant. This presentation reviews previous work regarding possible coupling of helioseismic modes to the magnetosphere and provides new results to support the conjecture. In addition, we revisit the interesting higher frequency signatures (10-15 mHz), associated with at least one of these events, observed in space and on the ground. These higher-frequency waves are observed as bursts of pulsations, occurring simultaneously over an extended region in local time, but having different polarizations and frequencies at each station.