Date: 2019/06/27(Thu)
Time: 14:45 - 16:15
Place: 8-103
Speaker: Ono Tatsuharu

Title:
The Observation of Jupiter’s lightning for the study of zonal wind formation mechanism

Abstract:
Jupiter is a gas giant planet. One of the Jovian features is a stripe. The stripe is called a band structure. The band structure consists of the east-west zonal jet. There are many theory to explain how to form the zonal jet. However, the debate is continuing. There is one theory that the zonal jet is formed by coupling small-scale eddies generated by cumulonimbus[Gierasch et al., 2000; Ingersoll et al., 2000]. To verify this theory, It is necessary to know the vertical convection occurring below the cloud layer. However, the exact location and frequency of vertical convection occurring below the cloud layer are unknown. Lightning observation help to obtain information about the presence of vertical convection below the cloud layer. However, in the previous researches, since it was observed at a long exposure(5-100s), it did not capture the feature of lightning, and it may be confused with other luminescence phenomena. In addition, since the observation time is only a few days in a few years for observation only at nightside, it can not be grasped about the accurate occurrence frequency. My purpose is understanding the formation mechanism of Jupiter's zonal wind maintained by small-scale eddies. For this purpose, we have to understand the relationship between vertical convection and zonal jet time variation. To know the vertical convection presence and information, we develop the instrument to do lightning observation and use it. A ground-based telescope is used to increase observation time. When using a ground-based telescope, it is necessary to make it possible to observe lightning from the dayside of Jupiter. And, in order to acquire the light curve of lightning and distinguish it from other light emissions, it is necessary to make observations in a short time of 50 ms or less. We are currently developing a Planetary Lightning Detector (PLD) to make these possible. In this time, I introduce the PLD shortly, show the analysis result of the test observation, and discuss it.