5:15 PM - 7:15 PM
[PPS05-P01] Development of Model Scattering from Venusian Lightning for observations comparing with JEM-GLIMS measurement of Earth lightning
Keywords:Venus, Lightning, Scattering Model, JEM-GLIMS
Lightning is a phenomenon formed by electric discharge through the atmosphere. Lightning activity has a relationship with the atmospheric activity. One of the generation mechanisms of lightning is cumulonimbus. Charge separation occurs when droplets are collided inside them. Lightning discharge occurs to resolve those charge separations. We can observe lightning using optical and electrical magnetic wave observations. Optical data shows the lightning's altitude and differentiates discharge type and other optical phenomena like meteors. ELF and VLF observations reveal characteristics of discharge, such as current. Some previous observations detected possible signals originating from Venusian lightning. LAC onboard AKATSUKI recorded a potential optical signal on March 1, 2020 (Takahashi et al., 2020). Lightning could help reveal the Venusian atmospheric dynamics. However, several issues prevent us from understanding Venusian lightning. Its existence, mechanism, and distribution are still poorly understood due to the time deficit in monitoring.
To enable us to achieve high-frequency monitoring observations, we have developed the Planetary Lightning Detector (PLD) for the 1.6-m Pirka telescope of Hokkaido University. From the data of observing Venus since 2021, we triggered several possible signals. We cannot rule out the possibility that all recorded light curves originate from noise or Cosmic rays. It might be disputable to conclude that we have detected lightning.
We compare the triggered waveforms with the model and Earth lightning light curve observed by JEM-GLIMS to test if the observed lightning is possible. JEM-GLIMS is a space mission to observe lightning and lightning-associated Transient Luminous Events (TLEs) such as sprites, elves, blue jets, and gigantic jets from the Exposed Facility (EF) onboard the International Space Station (ISS). JEM-GLIMS can operate the nadir observation of lightning and TLEs from the ISS orbital altitude (~400 km), and it is possible to measure the horizontal distribution and spatial and temporal evolution. JEM-GLIMS measured rare but comparable Earth lightning light curves with 100 milliseconds time scales like LAC observed. Lightning scattering duration time is still poorly understood. We use a scattering model (Luque et al., 2020) for understanding Earth's lightning characteristics. We investigate the long-timescale Earth lightning with the cloud structure obtained by the climate satellite. To reveal those relationships, we compare the simulated scattering waveforms and current observed by Extremely Low Frequency (ELF). We adjusted the atmosphere and cloud particle parameters for Venusian lightning, such as the reflective index. We used the vertical cloud distribution from Haus et al., 2016 to obtain the Venusian scattering light curve from a single instantaneous discharge. We found that the simulated Venusian lightning duration time is too short compared to the LAC observed. The time scale of the current waveform, which is the light source, is considered long, and we are verifying this by comparing it with the JEM-GLIMS observations and ELF. This time, we discuss the model's results, the JEM-GLIMS observations, and the comparison of LAC waveforms.
To enable us to achieve high-frequency monitoring observations, we have developed the Planetary Lightning Detector (PLD) for the 1.6-m Pirka telescope of Hokkaido University. From the data of observing Venus since 2021, we triggered several possible signals. We cannot rule out the possibility that all recorded light curves originate from noise or Cosmic rays. It might be disputable to conclude that we have detected lightning.
We compare the triggered waveforms with the model and Earth lightning light curve observed by JEM-GLIMS to test if the observed lightning is possible. JEM-GLIMS is a space mission to observe lightning and lightning-associated Transient Luminous Events (TLEs) such as sprites, elves, blue jets, and gigantic jets from the Exposed Facility (EF) onboard the International Space Station (ISS). JEM-GLIMS can operate the nadir observation of lightning and TLEs from the ISS orbital altitude (~400 km), and it is possible to measure the horizontal distribution and spatial and temporal evolution. JEM-GLIMS measured rare but comparable Earth lightning light curves with 100 milliseconds time scales like LAC observed. Lightning scattering duration time is still poorly understood. We use a scattering model (Luque et al., 2020) for understanding Earth's lightning characteristics. We investigate the long-timescale Earth lightning with the cloud structure obtained by the climate satellite. To reveal those relationships, we compare the simulated scattering waveforms and current observed by Extremely Low Frequency (ELF). We adjusted the atmosphere and cloud particle parameters for Venusian lightning, such as the reflective index. We used the vertical cloud distribution from Haus et al., 2016 to obtain the Venusian scattering light curve from a single instantaneous discharge. We found that the simulated Venusian lightning duration time is too short compared to the LAC observed. The time scale of the current waveform, which is the light source, is considered long, and we are verifying this by comparing it with the JEM-GLIMS observations and ELF. This time, we discuss the model's results, the JEM-GLIMS observations, and the comparison of LAC waveforms.