Science Highlights from the BARREL Antarctic Balloon Campaigns

Tuesday, 16 December 2014
Robyn M Millan, Dartmouth College, Hanover, NH, United States, John Glen Sample, University of California Berkeley, Berkeley, CA, United States, Michael McCarthy, Earth & Space Sciences, Seattle, WA, United States and David Miles Smith, Univ of California Santa Cruz, Santa Cruz, CA, United States
The Balloon Array for Radiation belt Relativistic Electron Losses (BARREL) is an Antarctic balloon investigation designed to study electron loss from Earth's radiation belts. Two BARREL balloon campaigns were carried out from Antarctic Research Stations SANAE IV and Halley VI in January-February 2013 and 2014. During each campaign, 20 small (~20 kg) balloon payloads were launched to an altitude of 38 km to maintain an array of payloads distributed in L-value and magnetic local time. Each balloon carried a NaI scintillator to measure the bremsstrahlung X-rays produced by precipitating relativistic electrons as they collide with neutrals in Earth’s atmosphere, and a DC magnetometer to explore the nature of Ultra Low Frequency temporal modulations of precipitation. We present several science highlights from BARREL. Precipitation was observed over a range of energies with temporal and spatial structure at a variety of scales. The combination of BARREL with in situ (e.g. Van Allen Probes, THEMIS) and ground-based (e.g. riometer, VLF) measurements provides a unique opportunity to study wave-particle interactions, and to quantify the spatial scale of energetic precipitation.