The Frequency Agile Solar RadiotelescopeThe Frequency Agile Solar Radiotelescope

AUI, NRAO, UCB, CIT, NJIT, UMd, UM

The InnovationThe Innovation

Ultra-wideband imaging spectroscopy of the solar atmosphere from the chromosphere to the outer corona with temporal, angular, and spectral resolution matched to the physical process that occur.

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TB x,y,ν , t,σ( )Brightness temperature as a function of position, frequency, time, and polarization

The entire solar atmosphere will be imagined in 3D from the mid-chromosphere to the outer-corona once every second!

FASR FASR SpecificationsSpecifications

(descope)(descope)

Frequency range 50 MHz - 21 GHz

Data channels, bandwidth, freq. channels, int. time

2/500 MHz/4000/20 ms

Number antennas

A: ~45 (990 pairs)B: ~15 (105 )C: ~15 (105)

Size antennas

A: 2 m B: 6 m C: LPD tiles or similar

Polarization Stokes IV(QU)

Angular resolution 20/9 arcsec

Footprint ~3 km

Field of View >0.5 deg

FASR A: ~2.5-21 GHz

FASR B: ~0.25-3 GHz

FASR C: ~50-300 MHz

Proposed site is OVRO

Coronal Magnetic Fields Coronal magnetography Spatiotemporal evolution of fields Role of electric currents in corona Coronal seismology

High energy solar physics Magnetic energy release Plasma heating and dynamics Electron acceleration and

transport Origin of SEPs

Drivers of Space Weather Birth & acceleration of CMEs Prominence eruptions Origin of SEPs Fast solar wind streams

The Science

The “thermal” solar atmosphere◦ Coronal heating - nanoflares◦ Thermodynamic structure &

dynamics ◦ Formation & structure of filaments

Solar Wind◦ Birth in network ◦ Coronal holes◦ Fast/slow wind streams◦ Turbulence and waves

Synoptic studies◦ Radiative inputs to upper atmosphere◦ Global magnetic field/dynamo◦ Flare statistics

The Science

Recent DevelopmentsRecent Developments• FASR DDP funded by NSF/ATM in 2006

Development of ultrawideband feeds and integrated amps initiated

• FST program funded by NSF/AST ATI in 2006RFI mitigation

• FASR Reference Instrument completedO&M Plan delivered in June 2007FASR descope/rescope

• Preliminary proposal submitted to the NSF/ATM MSI Opportunity program in January 2008

• Full proposal submitted to NSF in June 2008 for $25MFunding decision is imminent!

Definition and Variance of Spectral KurtosisDefinition and Variance of Spectral Kurtosis

1

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Dwyer (1983)

Vrabie (2003) Spectral Kurtosis

Nita (2007) Spectral Variability

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NkM

NkMVVar k

Performance and limitations of SK estimatorPerformance and limitations of SK estimator

Software Implementation of RFI excision algorithmSoftware Implementation of RFI excision algorithm

CASPER Hardware Implementation of RFI excision algorithmCASPER Hardware Implementation of RFI excision algorithm