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 B_z 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?


	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 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


	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


	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 B_z 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?