Stephen White Gyroresonance emission in FORWARD & Developments in radio telescopes Free-Free Opacity Two different modes, or circular polarizations ( =+1 o- mode, = 1 x-mode) X-mode has higher opacity, so becomes optically thick slightly higher in the chromosphere, while o-mode is optically thick slightly lower Polarization P = (T R T L )/(T R +T L ) = 0 for isothermal atmosphere because temperature is same in both layers In real atmosphere get polarization due to temperature gradient Gyroresonance emission Opacity results from electrons gyrating in coronal magnetic fields at f B = B Hz: linear scaling of B with frequency. In the non-flare (non-relativistic) corona this produces narrow resonances, i.e. physically very thin layers (tens of km). Opacity n B/( B/ l) (T/mc 2 sin 2 ) s-1 where s = 1, 2, 3, is the harmonic Because T/mc 2 is 1/3000, opacity drops by 3 orders of magnitude from one layer to the next Big difference in opacity of two polarizations of electromagnetic waves: extraordinary mode interacts more with electrons than ordinary mode Gyroresonance opacity at low harmonics Model sunspot gyroresonance layers OVSA Expansion Project Dale E. Gary Professor, Physics, Center for Solar-Terrestrial Research New Jersey Institute of Technology 7 8 09/24/2012Prototype Review Meeting 09/24/2012Prototype Review Meeting 10 LOFARs first solar image 11 Murchison Widefield Array Joint US/Australian project located at the candidate SKA site in Western Australia (miles and miles from anywhere) US players are Haystack, Harvard/CfA, MIT Australian players are CSIRO/ATNF, Curtin University (WA) with a lot of support from Australian (federal) and West Australian (state) governments Covering the high-frequency end of the LOFAR range, same technique, same science goals. Using GPU units to do their data processing! 12 MWA station and 32T layout Consortium with PAPER project in the future 13 The Long Wavelength Array US project involving Naval Research Laboratory, U. New Mexico, Los Alamos, Virginia Tech, U. Texas, NRAO, AFRL, Zebra patterns more common in flares Unexpected fine structure above 60 MHz Wrigglers at 10 millisecond resolution Type III burst at RSTN (3 seconds, 0.15 MHz) At LWA1 resolution Allen Telescope Array 21 LOFARs first solar image ATA solar image 22 Siberian Solar Radio Telescope (SSRT) 23 EVLA: better frequency, time coverage 24 EVLA observation of the Sun at F10.7 ALMA 26 ALMA can observe the Sun! Will be wonderful for flares (but small FOV) and chromosphere studies IF we can get observing time 27 Solar Submillimeter Telescope (Argentina/Brazil) 28 The Sun