Remote Sensing of Space Environment Using Ground-Based and Satellite-Borne Instruments
With Rezy Pradipta
Institute for Scientific Research, Boston College
Space Propulsion Lab, Massachusetts Institute of Technology
Faculty Host: Min-Chang Lee
Refreshments will be served outside Room 339 at 3:45 p.m.
Abstract: Space can be a hostile environment for astronauts and spacecrafts. It is important to study space environment and its effects on systems that operate within it and on the ground. Rezy Pradipta will report on the control study of space environment at Arecibo (Puerto Rico) and Gakona (Alaska). In these experiments, HF and/or VLF radio waves were injected from the ground. Radio/radar, optical, and satellite-borne instruments were used to diagnose the radio wave interactions with space plasmas. These active experiments are aimed at probing space environment to improve communications and space surveillance and remove energetic charged particles from radiation belts for satellite remediation.
Rezy Pradipta’s talk will focus on the diagnosis of acoustic-gravity waves (AGWs) that may trigger widespread space plasma turbulence. These AGWs can be generated naturally by, for example, extensive anomalous heat sources in prolonged heat wave events, as observed in Arecibo experiments. AGWs can also be produced by injected high-power HF radio waves, as demonstrated in Gakona experiments. It is found that injected HF waves and induced AGW can create large ionospheric ducts. These artificial waveguides facilitate whistler wave propagation from the ionosphere into the radiation belts to clean the trapped hazardous charged particles. Hence, radio wave injection experiments are conducive to the investigation of space environment and the development of techniques for safe operations of instruments and systems in space.
About the Speaker: Rezy Pradipta completed his B.S., M.S., and Ph.D. at the Massachusetts Institute of Technology (MIT) in 2006, 2007, and 2012, respectively, in physics, applied math, and nuclear science and engineering. He joined the Institute for Scientific Research at Boston College (BC) recently as a postdoctorate for space research. He has been conducting field experiments in the past nine years at Arecibo Observatory, Puerto Rico, and Gakona, Alaska, using extensive radio/radar and optical instruments as well as GPS satellites for diagnosis of space environment. These experiments are aimed at investigating HF radio wave and VLF whistler wave interactions with space plasmas, to improve communications, space surveillance, and remove hazardous energetic charged particles from radiation belts for satellite remediation. He also carried out experiments at Gakona to simulate gravity wave generation caused by natural or HF wave created anomalous heat sources. In 2006, Rezy Pradipta received a certificate for Recognition for Distinguished User of the 305-m diameter Arecibo radar from the National Astronomy and Ionosphere Center (NAIC) of Cornell University. He was invited to give tutorial lectures at Polar Aeronomy and Radio Science (PARS) Summer School, hosted by University of Alaska Fairbanks (UAF), in 2009, 2011 and 2012. He was also an invited speaker at the 2011 IEEE ICOPS (International Conference on Plasma Science) as well as at the 2012 RF Ionospheric Interactions Workshop, sponsored by NSF in cooperation with AFRL, ONR, and UAF.