One-to-one correlation between periodic VLF emissions (t~5.6) and short-period magnetic pulsations was found at Syowa Station (L~6) in Antarctica on August 8, 1981. The periodic VLF emissions were observed uner extremely quiet geomagnetic conditions (Kp=0-1). Fortunately, the periodic VLF emissions were recorded simultaneously on the ground at Syowa and on the ISIS 2 satellite. At ISIS 2 satellite level (~1400 km altitude), the periodic emissions showed one-to-one correspondence with the periodic emission observed at Syowa in the wide latitude range from L~3.5 to L~14.0, and also in the region about 2 hours away from Syowa in magnetic local time. From the ground data, the intensity of the H component of magnetic pulsations associated with the periodic VLF emissions is about 0.02 nT, approximately 5 times larger than that of the D component of magnetic pulsations. Magnetic pulsations associated with the periodic emission have constant frequency and show a ''linelike'' frequency-time spectrum. The amplitude of magnetic pulsations observed at Mizuho Station, about 270 km poleward from Syowa along the geomagnetic meridian plane, is approximately 4 times less than that at Syowa. For the origin of the short-period magnetic pulsations it is suggested that the periodic precipitating electron fluxes induced by periodic VLF waves would modify the ionospheric conductivity. The periodic enhancements of conductivity in the ionospheric D and E regions would modify the Sqp current flows in the ionosphere, resulting in the magnetic variations observed on the ground. |