The Frequency Agile Solar Radiotelescope (FASR)

1. The Frequency Agile Solar Radiotelescope (FASR) Dale E. Gary New Jersey Institute of Technology

2. NJIT Center for Solar Terrestrial Research

3. FASR Instrument (Antennas) Three arrays, 4.2 km baselines NJIT Center for Solar Terrestrial Research

4. NJIT Center for Solar Terrestrial Research

5. FASR Instrument (Receivers) Broadband RF transmission, Digital FX Correlator NJIT Center for Solar Terrestrial Research

6. FASR Science Goals Designed to be the world’s premier solar radio facility for at least two decades after completion. Full capability to address a broad range of solar science: • Nature and evolution of coronal magnetic fields • Physics of flares • Drivers of space weather • Physics of the quiet solar atmosphere NJIT Center for Solar Terrestrial Research

7. Objectives to Measurements NJIT Center for Solar Terrestrial Research

8. Model spectra along 2 lines of sight: a) negative polarity sunspot, b) positive polarity sunspot. The coronal temperature and the magnetic field strength can be read directly from the spectra. Magnetic Field Spectral Diagnostics Model from Mok et al., 2004; Simulation from Gary et al. 2004 NJIT Center for Solar Terrestrial Research

9. 2D Magnetogram • B map deduced from 1—24 GHz spectra (b) match the model (a) very well, everywhere in the region. (c) is a comparison along a line through the center of the region. • The fit only works down to 119 G (corresponding to f = 3 fB = 1 GHz) from Gary et al. 2004 NJIT Center for Solar Terrestrial Research

10. Objectives to Measurements NJIT Center for Solar Terrestrial Research

11. With sufficient polarization sensitivity, Bl can be deduced everywhere down to ~ 20 G using: where n is the spectral index Bl from Free-Free Emission from Gelfreikh, 2004—Ch. 6 from Gary & Hurford, 2004—Chapter 4 NJIT Center for Solar Terrestrial Research

12. Objectives to Measurements NJIT Center for Solar Terrestrial Research

13. Upper panels show radio “depolarization line” (DL) at a single frequency due to mode-conversion at a quasi-transverse (QT) layer, vs. photospheric neutral line (NL). Using FASR’s many frequencies, a QT surface can be mapped in projection. The surface changes greatly with viewing angle. Magnetic Topology from QT Layer from Ryabov, 2004—Chapter 7 NJIT Center for Solar Terrestrial Research

14. Prototyping Efforts • Green Bank Solar Radio Burst Spectrometer (feed development) • FASR Subsystem Testbed--FST (design platform, RFI mitigation, solar observations) • French Activities (RFI mitigation, FPGA technology) NJIT Center for Solar Terrestrial Research

15. Green Bank Solar Radio Burst Spectrometer Feed Development • 20-70 MHz system using “fat dipole” • 50-250 MHz feed on 45-foot telescope • 200-1070 MHz on 45-foot telescope http://www.astro.umd.edu/~white/gb/ NJIT Center for Solar Terrestrial Research

16. FST System • Hardware • 1-9 GHz RF • 500 MHz instantaneous BW • Record full-res time-domain signal, off-line processing • Block Diagram NJIT Center for Solar Terrestrial Research

17. Results (RFI) • 10000-pt spectra (dn = 50 kHz), 10 ms time resolution sample of local interference signal • Goal is to identify and excise interference in real time • Hiro Kawakubo and Chris Ruf (U Mich) are studying use of kurtosis statistic Frequency Time NJIT Center for Solar Terrestrial Research

18. Results (Satellites) • First Fringes (GPS satellite, L1 signal, 1575.42 MHz) NJIT Center for Solar Terrestrial Research

19. Results (Satellites) • Geostationary Satellite Galaxy 10R • Can phase information be used for calibration? • Overlapping channels are linearly (H and V) polarized, which offers possibility of linear polarization calibration NJIT Center for Solar Terrestrial Research

20. Results (Solar) B5.1 Flare (2006 Apr 05) 20 s of FST Amplitude Data NJIT Center for Solar Terrestrial Research

21. FST Amplitude & Corrected Phase Burst locations essentially identical from burst to burst, and from one polarization to another NJIT Center for Solar Terrestrial Research

22. Status and Conclusion • FASR is being designed to address an extremely rich range of solar science, utilizing state-of-the-art technology. • Some aspects of the instrument are currently being prototyped. • Most recent proposal received highest recommendation, but funding has been reduced and delayed by funding agency. • Next step is to construct a 10-element prototype array, to be ready by 2010. Proposal to be submitted as soon as possible. NJIT Center for Solar Terrestrial Research

23. NJIT Center for Solar Terrestrial Research

24. FASR Endorsements • 2001 Astronomy & Astrophysics Survey Committee • Ranked as one of 17 priority projects for this decade • one of 3 solar projects, with ATST and SDO • 2003 Solar and Space Physics Survey Committee • Ranked as top priority in small (<$150 M) projects • 2002-2004: Design Study (NSF/ATI) • 3 workshops for community input • Science consensus, hardware and software design options, and development of management plan. • 2004-2006: FASR Long-Lead Prototyping Proposal (NSF/ATI) NJIT Center for Solar Terrestrial Research

25. FASR Signal Path Element RF Converter Room IF Processor Room LO distribution Front-end Analog fiber- optic cable Polyphase Filter Bank RF-IF converter 12-bit Digitizer 1-bit Sampler Correlator and DSP Back-end From other antennas LAN Internet Data Storage On-line Calibration Control Room Burst monitor(s) RFI monitor(s) Computing System NJIT Center for Solar Terrestrial Research

26. FASR Science Community Input • International Science Workshop, 2002 May, Green Bank, WV • Special session, 2002 American Astronomical Society meeting • Kluwer ASSL* Book: Solar & Space-Weather Radiophysics (17 chapters on all aspects of radiophysics of the Sun and inner heliosphere, will appear by end of summer) *Astrophysics & Space Science Library NJIT Center for Solar Terrestrial Research

27. Accurate simulation of FASR coronal magnetograms of potential and non-potential active region, and difference compared with current-density map from the model. Coronal Magnetograms from Gary et al. 2004 NJIT Center for Solar Terrestrial Research