Summary of the PPB wave observations

 

                      Prof. Hisao Yamagishi, NIPR

 

It was planned to launch three balloons with identical instrumentation with a spatial separation of ~150 km, in order to study spatial and temporal variations of the phenomena occurring in the boundary regions in the magnetosphere. The first balloon, PPB No.9, was launched on 6 January, but the flight was terminated 2 hours after the launch due to a trouble in cut-down command system. After a week of waiting, PPB No.8 and 10 were launched successfully at 06:49 and 12:16 UT on 13th January. The balloons reached a ceiling altitude of 32 km and moved westward at a speed of about 20 km/h. When they traveled halfway round the Antarctica on 25 January, the wind system in the stratosphere changed directions. PPB No.8 was stagnated there for a week, while PPB No.10 moved towards lower latitudes, and dropped on the ocean 300 km offshore of Patagonia on 31 January 2003. After a week of stagnation, PPB No.8 started to move towards lower latitudes on 31 January, and seemed to drop on the ocean 500 km offshore of Patagonia on 7 February 2003.

During these flights, the balloons traversed magnetic latitude range of 50~70 degrees, and the separation of the balloons changed from 150km to about 1500km. Observed data were directly transferred to Japan by Iridium satellite telephone system, as well as telemetered to the ground at Rothera Station in Antarctic Peninsula. The wave instrument onboard observed Pc1 pulsations, ELF hiss, polar chorus and auroral hiss. Daily summary of the wave observation can be seen in this home page. Some of the wave phenomena were observed simultaneously, and some were not by the two balloons, reflecting spatial extent of the phenomena. Pc1 pulsations consisted of transient bursts with decreasing amplitude lasting for ~20s, and continuous type emissions lasting for more than 10 minutes. Example of this waveform can be seen in this homepage.

    We have made a campaign observation with the ELF/VLF wave instrument onboard Akebono satellite. Please let me know if you find, in your ground observation, some wave phenomena corresponding to the balloon observation.