2fp radio emission from the vicinity of the Earth's foreshock: WIND observations

Abstract

We analyze 2fp radio emission observed during a perigee pass in August 1995 when the WIND spacecraft was between 47 and 72 RE from Earth and upstream of the electron foreshock. The WAVES experiment on WIND measures the direction of arrival and complete polarization state of the 2fp radiation. We found no evidence for significant linear or circular polarization. For one period when we were able to utilize the direction finding capability to determine the actual 2fp source location, using an interplanetary shock as a diagnostic, the radio emitting region was confirmed to lie within the electron foreshock near the contact point. We indicate how such remotely observed 2fp emissions can be used to monitor the response of the electron foreshock to instantaneous changes in the interplanetary magnetic field.