Solar wind control of polar chorus

The intensity of chorus as observed at several high latitude ground station s in the Antarctic is highly correlated with the solar wind dynamic pressur e exerted on the magnetopause boundary. In two different cases, intense cho rus and associated precipitation measured as riometer absorption were abrup tly interrupted by several minutes of deep quieting. Satellite measurements of solar wind dynamic pressure showed the intensity of chorus to rapidly r espond to magnetospheric compression and relaxation over an extended region as evidenced by the fact the effect was observed at multiple sites.