Notes

Outline

FASR at low frequencies The NSF will only fund FASR if the US solar community tells them to. In order to achieve FASR, we have to persuade, primarily, the US solar community that it is a project that will be useful to them For this reason we will make it as easy as possible for everyone to use FASR data: this means providing images on demand Original version of  FASR started at 500 MHz for several reasons: - we thought that 500 – 20000 MHz might be technically feasible   with a single set of telescopes with a reasonable budget - we had two strong science goals (flares and coronal magnetic   fields) that could be addressed with this range - little interest in lower frequencies in the US: lack of relevance   to main science themes in US solar science Frequency ranges: 2 – 20 GHz: coronal magnetic fields 2 – 30 GHz: flare gyrosynchrotron emission 0.5 – 1 GHz: decimeter emission (no imaging)

Space Weather Space Weather changed that: it became a priority for US science and made it essential to consider Space Weather applications of FASR; in fact, made it dangerous to propose FASR without a significant Space Weather component Hence we have to identify the role that FASR can play in Space Weather and what abilities it needs to achieve this role We have to convince them that FASR really will make a contribution, not just image Type IIIs Space Weather wants prediction of geomagnetic storms (power disruption) prediction of SEPs (hazard to spacecraft/astronauts) prediction of ionospheric conditions (communication) assessment of impacts of Sun directly, e.g. cell phones

Low Frequency Options for FASR Cheapest option: stay at 500 MHz lower cutoff “Friend of LOFAR” option: go down to 200 MHz and leave lower frequencies to LOFAR - relies on present LOFAR plans being realized - relies on LOFAR being in the US - relies on LOFAR donating a beam to the Sun, including a “Dutch beam” (> 160 MHz) “European” or “standard” (?) option: go down to the FM band at 100 MHz but this misses type IIs and type IVs Expensive option: go down to 30 MHz and deal with the ionosphere

Space Weather with FASR Thermal imaging of prominences: > 10 GHz; but what’s new? Gyrosynchrotron from CMEs: 100 – 400 MHz; better than LASCO? Thermal emission from CMEs at 100 – 1000 MHz Thermal emission from CMEs at 10 - 20 GHz (April 18)? Disk observations of these phenomena not available from coronagraphs History of energetic particle acceleration/energy release through the corona from low to high heights Decimetric signatures of CMEs or particle events – known to Monique? Type II bursts: < 100 MHz; but is there a direct connection to SW? Type IIIl events: < 100 MHz; possible relation to SEPs Moving Type IV events: < 100 MHz; possible relation to CMEs Measurements of Bz in eruptive prominences: > 10 GHz; not demonstrated Coronal holes at high frequencies: what is different from SXR/10830? Are the puzzling radio properties related to fast streams?