SOLAR-T: terahertz photometers to observe solar flare emission on stratospheric balloon flights

摘要

A new solar flare spectral component has been found with intensities increasing for larger sub-THz frequencies,spectrally separated from the well known microwaves component, bringing challenging constraints for interpretation.Higher THz frequencies observations are needed to understand the nature of the mechanisms occurring in flares. A twofrequencyTHz photometer system was developed to observe outside the terrestrial atmosphere on stratospheric balloonsor satellites, or at exceptionally transparent ground stations. 76 mm diameter telescopes were designed to observe thewhole solar disk detecting small relative changes in input temperature caused by flares at localized positions at 3 and 7THz. Golay cell detectors are preceded by low-pass filters to suppress visible and near IR radiation, band-pass filters,and choppers. It can detect temperature variations smaller than 1 K with time resolution of a fraction of a second,corresponding to small burst intensities. The telescopes are being assembled in a thermal controlled box to which a dataconditioning and acquisition unit is coupled. While all observations are stored on board, a telemetry system will forwardsolar activity compact data to the ground station. The experiment is planned to fly on board of long-durationstratospheric balloon flights some time in 2013-2015. One will be coupled to the GRIPS gamma-ray experiment incooperation with University of California, Berkeley, USA. One engineering flight will be flown in the USA, and a 2weeks flight is planned over Antarctica in southern hemisphere summer. Another long duration stratospheric balloonflight over Russia (one week) is planned in cooperation with the Lebedev Physics Institute, Moscow, in northernhemisphere summer.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.