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The Frequency Agile Solar Radiotelecope

The Frequency Agile Solar Radiotelecope. T. S. Bastian and the FASR Team. NRAO, NJIT, UMd, Berkeley, NSO, NRL, Obs. Paris. FASR will be a ground based solar-dedicated radio telescope designed and optimized to produce images over a broad frequency range with

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The Frequency Agile Solar Radiotelecope

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  1. The Frequency Agile Solar Radiotelecope T. S. Bastian and the FASR Team NRAO, NJIT, UMd, Berkeley, NSO, NRL, Obs. Paris

  2. FASR will be a ground based solar-dedicated radio telescope designed and optimized to produce images over a broad frequency range with • high angular, temporal, and spectral resolution • high fidelity and high dynamic range • As such, FASR will address an extremely broad science program. • An important goal is to mainstream solar radio observations by providing a number of standard data products for use by the wider solar physics community.

  3. from S. Krucker’s RHESSI web pages

  4. Nobeyama Radioheliograph

  5. FASR Specifications

  6. Array configuration “self-similar” log spiral XC

  7. model snapshots 5 GHz Imaging 10 min synth. TRACE: 6 Nov 1999 22 GHz 22 GHz (no thermal noise)

  8. FASR Key Science • Nature & Evolution of Coronal Magnetic Fields Measurement of coronal magnetic fields Temporal & spatial evolution of fields Role of electric currents in corona Coronal seismology • Flares Energy release Plasma heating Electron acceleration and transport Origin of SEPs • Drivers of Space Weather Birth & acceleration of CMEs Prominence eruptions Fast solar wind streams Relation to SEPs

  9. from J. Lee

  10. Active region showing strong shear: radio images show high B and very high temperatures from Lee et al (1998)

  11. 17 GHz intensity 17 GHz circ. pol. 34 GHz intensity Magnetic field lines in the solar corona illuminated by gyrosynchrotron emission from nonthermal electrons. Nobeyama RH

  12. FASR Key Science • Nature & Evolution of Coronal Magnetic Fields Measurement of coronal magnetic fields Temporal & spatial evolution of fields Role of electric currents in corona Coronal seismology • Flares Energy release Plasma heating Electron acceleration and transport Origin of SEPs • Drivers of Space Weather Birth & acceleration of CMEs Prominence eruptions Fast solar wind streams Relation to SEPs

  13. from Aschwanden & Benz 1997

  14. Type U bursts observed by Phoenix/ETH and the VLA. from Aschwanden et al. 1992

  15. Two ribbon flare observed by the VLA on 17 Jun 89. 6 cm (contours) Ha (intensity) from Bastian & Kiplinger (1991)

  16. FASR Key Science • Nature & Evolution of Coronal Magnetic Fields Measurement of coronal magnetic fields Temporal & spatial evolution of fields Role of electric currents in corona Coronal seismology • Flares Energy release Plasma heating Electron acceleration and transport Origin of SEPs • Drivers of Space Weather Birth & acceleration of CMEs Prominence eruptions Fast solar wind streams Relation to SEPs

  17. C3 20 April 1998 C3 C2 C2 10:04:51 UT 10:31:20 UT 10:45:22 UT SOHO/LASCO 11:49:14 UT

  18. Noise storm Bastian et al. (2001)

  19. LoS a Rsunf (deg) ne (cm-3) B(G) nRT (MHz) Bastian et al. (2001)

  20. 15 April 2001 Nancay Radioheliograph: 421 MHz Maia et al 2003

  21. NoRH detection of an “EIT wave” at 17 GHz: possibly the signature of the expanding edge of a coronal mass ejection at the base of the corona. White et al 2002

  22. FASR Science (cont) • 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

  23. 20 Feb 1995 “network flares” Yohkoh SXT VLA 2 cm SXT Krucker et al (1997)

  24. Synoptic studies 17 GHz B gram SXR

  25. The FASR key science objectives are an excellent match to elements of SEC science goals and applications-driven LWS research. To fulfill its goal of mainstreaming the use of radio imaging spectroscopy, a key project requirement is to integrate FASR data analysis and data products under the software umbrella used by relevant NASA missions and other ground based observatories. It is also worth exploring whether data from NASA missions and other observatories could be integrated into FASR operations in real time.

  26. Status and Plans The decadal review of the NAS/NRC Astronomy and Astrophysics Survey Committee recommended an integrated suite of three ground and space based instruments designed to meet the challenges in solar physics in the coming decade. These are: Advanced Technology Solar Telescope (O/IR) Frequency Agile Solar Radiotelescope (radio) Solar Dynamics Observatory (O/UV/EUV) More recently, the decadal review of theNAS/NRC NAS/NRC Solar and Space Science Survey Committeeranked FASR as itsnumber one priorityfor small projects (<$250M).

  27. 2001: Proposal to NSF Advanced Technologies and Instrumentation program (2 years) accepted 2002-3: Design Study (NSF/ATI) underway International Science Definition Workshop May 23-25 First FASR Technical Meeting Aug 1-2 First FASR Data Management Meeting spring, 2003 Site survey Configuration studies Simulations Calibration strategies Costing 2003-5: Design and Development Prototype major elements: NSF MRI Refine design, hardware and software 2005-9: Construction

  28. http://www.ovsa.njit.edu/fasr

  29. FASR CALIBRATION SUMMARY DATA PRODUCTS (maps, spectra, light curves) - Absolute positions to <1 arcsec (10-20 GHz) - Absolute flux (and brightness temperature) calibration to ~5% - Relative (frequency to frequency) calibration to <1% TECHNIQUES Phase calibration: - Intrinsically stable design: simplified antenna-based electronics, temperature stabilization, buried optical fibers - Primary phase calibration against cosmic standards before/after observing day - Secondary phase calibration (troposphere, ionosphere) + geostationary satellites + self-calibration algorithms + other alternatives(water vapor, wave-front sensing) Flux calibration: - Observation of known cosmic sources before/after observing day - Secondary gain monitoring using front-end noise sources

  30. FASR DATA ACQUISITION and DATA HANDLING - 1 Observing plan - Full disk field of view - Uninterrupted solar viewing during daylight hours (no calibration gaps) - Real-time, automated frequency- and time-dependent gain control 8 parallel signal paths from antennas (RCP and LCP for 20-300, 200-2500, 3000-12000, 12000-24000 MHz ranges) Generation of interim database - Programmable, but predefined correlation sequences use rapid time multiplexing of frequency bands within each range. - High spectral resolution correlation within each frequency band populates an interim database (10 Tbytes/day) which expires in ~24 hrs - Interim database has sufficient time/frequency resolution to meet all observational and frequency-excision requirements. - Time-independent calibration parameters and interference excision are applied in real-time as interim database is populated.

  31. FASR DATA ACQUISITION and DATA HANDLING - 2 Generation of archival databases Observing modes are implemented by flexible, parallel selection and averaging of the interim database. The archival data base will be the starting point for most data analysis. Typical microwave databases: - Coronal magnetograms (acquired high-freq, low-time - Burst observations (acquired with high-time, freq resln) - Solar monitoring - Campaign- or GI-driven database (TBD as requested) - Result is a set of parallel, application-driven archival databases, generated with latency of 10 m to ~10h, to which time-dependent calibration factors have been applied. Total size: ~100 Gbyte/day - Most archival databases will be generated automatically, but provisions will be made for manual selection of data based on quick look data and input from external sources (e.g., S/C data or other observatories)

  32. FASR DATA ACQUISITION and DATA HANDLING - 2 Data products Quick look products (generated with latencies of 10-60 minutes) Light curves at microwave frequencies Burst spectra at microwave frequencies, including preliminary maps. Dynamic spectra at metric and decimetric frequencies, (including locations and event classification) Additional operational data products Coronal magnetic field maps (~30 minute latency) Research-oriented data products Imaging spectroscopy at metric, decimetric and microwave frequencies. Derived parameter maps (eg coronal magnetic field, temperatures, density maps, etc.)

  33. Context: Other Radio Initiatives • LOFAR – a LOw Frequency ARray operating from ~20-150 MHz. Presently involves NRL, NFRA, and MIT. • EVLA – Extended Very Large Array. Phase 1 will replace correlator, data Xmit, and fill out complement of Rx to provided continuous coverage from 1-50 GHz. Phase 2 will cross-link the VLA, VLBA, and add several new elements. • ALMA – Atacama Large Millimeter Array. Joint NRAO/ESO project to build a mm/submm array of sixty-four 12 m antennas in Chile. • ATA – Allen Telescope Array, formerly the 1HT. Named for sugar daddy Paul Allen, the ATA is a SETI Institute project. It will be composed of 350 antennas of 6.1 m each and operate between 0.5-11 GHz. • SKA – Square Kilometer Array. Next big thing. Large international consortium. Won’t happen for >10 yrs. None of the above is solar dedicated

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