Solar Observations with LLAMA

CRISTIANI, GERMÁN D.; MANDRINI, CRISTINA H.

Salta

Workshop; Science with LLAMA; 2022

MinCyT

Solar flares are transient events of sudden energy release in amounts of up 10^33 erg with characteristic times of about hundreds of seconds. Flares and associated phenomena, such as coronal mass ejections (CMEs), are the most dynamic aspects of the solar corona that involve the destabilization of the large scale magnetic field. When observed in radio wavelengths, flares are called radio bursts. Radio observations of these phenomena provide an invaluable source of information about the physical processes involved due to the high variety of emission mechanisms in this spectral range. Higher frequencies radio observations impose the most serious constraints to solar flare models. Solar radio telescopes have evolved following the scientific interests to achieve data at unexplored ranges. In the 80's and 90's, several solar radio-telescopes were built in the microwave range (Owens Valley Solar Array, OVSA, at 1-18 GHz; Nobeyama Radioheliograph, at 17 and 34~GHz, etc). The Solar Submillimeter-wave Telescope (SST, 212 and 405 GHz) started obsrving the Sun at submillimeter wavelengths in the 21st century. A remarkable discovery, at frequencies above 100 GHz during flares, is the existence of the so-called ``THz component", a spectral component with an increasing profile at the highest observable frequencies (up to 405 GHz) towards the THz domain. This new spectral component is difficult to explain as bremsstrahlung or gyrosynchrotron emission. LLAMA will bring data at an unexplored spectral range (> 400 GHz) and will reach the best spatial resolution ever registered by solar radio-telescopes. The antenna is specially designed to be able to point towards the Sun without producing damages in its compounds. Visible and infrared radiation will be scattered by the de-polished surface of the dish, avoiding excessive energy concentration on the secondary reflector.Besides the analysis of transient phenomena, LLAMA will be extremely valuable for the study of the chromospheric temperature structure, improving our understanding of the energy transport along the solar atmosphere.