The Frequency Agile Solar Radiotelescope AUI, NRAO, UCB, CIT, NJIT, - - PowerPoint PPT Presentation

The Frequency Agile Solar Radiotelescope

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

The 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

• ccur.

฀  T

B x,y,,t,

 

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 Specifications (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 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 2006

RFI mitigation

• FASR Reference Instrument completed

O&M Plan delivered in June 2007 FASR descope/rescope

• Preliminary proposal submitted to the NSF/ATM MSI

Opportunity program in January 2008

• Full proposal submitted to NSF in June 2008 for $25M

Funding decision is imminent!

Definition and Variance of Spectral Kurtosis



  



1 / 2 N n N ikn n k

e x X



k k k

iB A X  

2 2 k k k

B A P  

2 2 2 k k k k k

P P P     

2 2 4

) (

k k k

A A f K 

2 2 2 2 4

2 ) (

k k k k

X X X f SK  

              1 1

2 2 2 2 2 k k k k k

P P M M M V  

Dwyer (1983) Vrabie (2003) Spectral Kurtosis Nita (2007) Spectral Variability

 

       ) 1 2 / ( ,..., 1 , / 4 2 / , , / 24

2

N k M N k M V Var

k

Performance and limitations of SK estimator

Software Implementation of RFI excision algorithm

CASPER Hardware Implementation of RFI excision algorithm