Optical signatures of the outer radiation belt boundary.

Earth's radiation belts are a dynamic region around the Earth where energetic charged particles orbit, which wise humans and robots stay away from. We show observations of optical emissions in all-sky camera that mark the outer boundary of the radiation belt. The result could be used to identify the outer extent of the radiation belts through simple white light images of the aurora.   

[Nithin Sivadas, Josh Semeter, Toshi Nishimura & Sebastijan Mrak. Geophysical Research Letters.




Coincidental TID production by tropospheric weather during the August 2017 total solar eclipse.

During the total solar eclipse through the United States in 2017, electron density perturbations in the ionosphere were observed over the path of the totality. These were thought to be evidence for "bow waves" induced by the moon's shadow racing across the Earth's surface. However, we show that this is unlikely the case, and that the perturbation is likely caused by a thunderstorm in the eclipse path.   

[Sebastijan Mrak, Josh Semeter, Toshi Nishimura, Michael Hirsch, Nithin Sivadas. Geophysical Research Letters.



Simultaneous measurements of substorm-related electron energization in the ionosphere and the plasma sheet.

Intense aurora is sometimes accompanied by energetic electrons. We use ground and space-based measurements to constrain the source of the energetic electrons (~ 300 keV) to distances beyond 9 earth radii in the plasma sheet, possibly  scattered by Electro-magnetic Ion Cyclotron (EMIC) waves. 

[Nithin Sivadas, Josh Semeter, Toshi Nishimura, Antti Kero. Journal of Geophysical Research: Space Physics.]



A nano-satellite mission to study charged particle precipitation from the Van Allen radiation belts caused due to Seismo-Electromagnetic emissions.

Describes the mission and science goals of the IIT Madras Nano Satellite (iitmsat). This university satellite carries a high energy particle detector that can measure electrons (1-15  MeV) and protons (1-100 MeV) precipitating from the van allen radiation belts. 

[Nithin Sivadas, Akshay Gulati, Deepti Kannapan, Ananth S Yalamarthy, Ankit Dhiman, Arjun Bhagoji, Athreya Shankar, Nitin Prasad, Harishankar Ramachandran, David Koilpillai. The 5th Nano Satellite Symposium.]