1. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research1 / 44 FASR Flare Science: Lessons from the Nobeyama Radioheliograph Dale E. Gary New Jersey Institute of Technology

2. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research2 / 44 Outline The FASR conceptThe FASR concept The NoRH specifications that are important for flare researchThe NoRH specifications that are important for flare research What we have learned about flares from NobeyamaWhat we have learned about flares from Nobeyama How FASR will use these lessonsHow FASR will use these lessons

3. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research3 / 44 FASR Instrument (Antennas) Three arrays, 6 km baselines (<1” at 20 GHz) Array Designation Number of Antennas Frequency Range Antenna Size FASR-A High Frequency Array ~1002-24 GHz2 m FASR-B Low Frequency Array ~600.2-3 GHz6 m FASR-C Log-Periodic Dipole Array ~4020-300 MHz Log- dipole

4. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research4 / 44

5. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research5 / 44 FASR Instrument (Receivers) Broadband RF transmission, Digital FX Correlator QuantitySpec Frequency Resolution 0.1% (FASR-C) 1% (FASR-A,B) Time Resolution 10 ms (FASR-B,C) 100 ms (FASR-A) PolarizationStokes IV (QU) Instantaneous Bandwidth~1 GHz

6. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research6 / 44 FASR Signal Path Correlator and DSP 12-bit Digitizer Analog fiber- optic cable On-line Calibration Data Storage LAN Internet Burst monitor(s) RFI monitor(s) RF Converter Room IF Processor Room Control Room RF-IF converter Back-end LO distribution Polyphase Filter Bank 1-bit Sampler Front-end Element Computing System From other antennas

7. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research7 / 44 FASR-A

8. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research8 / 44 FASR-B,C

9. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research9 / 44 FASR Calibration Must calibrate for  Instrumental/environmental changes (e.g. temperature)  Troposphere (weather)  Ionosphere Design will emphasize instrumental stability (no rapid secular changes) Use satellite signals for initial instrument calibrations Use cosmic sources for antenna (amp/phase) calibration before sunrise and after sunset Use self-cal (plus noise cal source) during the day (FASR-A,B) Use GPS measurements of TEC tip-tilt (FASR-B,C)

10. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research10 / 44 FASR Science Community Input International Science Workshop, 2002 May, Green Bank, WV Special session, 2002 American Astronomical Society meeting Kluwer/Springer Astrophysics and Space Science Library Book: Solar & Space-Weather Radiophysics (17 chapters on all aspects of radiophysics of the Sun and inner heliosphere)

11. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research11 / 44 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: 1. 1.Directly measure coronal magnetic fields 2. 2.Image Coronal Mass Ejections (CMEs) 3. 3.Obtain radio spectral diagnostics of particle acceleration / energy release, with excellent spatial and temporal resolution 4. 4.Image radio emission from shocks (type II), electron beams (type III), and other bursts over heights 1-2.5 R s 5. 5.Construct 3D solar atmospheric structure (T, B, n e ) over a wide range of heights

12. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research12 / 44 NoRH Legacy for Flare Science Instrument parameters relevant to flare research Key flare results based on selection of 28 papers  Morphology  Dual-frequency studies  Timing  Correlation with X-rays Stephen White

13. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research13 / 44 NoRH Instrument Parameters (Relevant to Flare Studies) Two frequencies (17 & 34 GHz)  usually both optically thin in flares  good for both thermal and nonthermal emission Full Sun field of view Solar-dedicated, solar-optimized Dual circular polarization Spatial resolution 15” (17 GHz), 8” (34 GHz) Redundant baseline calibration scheme using Sun as calibration source 84 antennas (1500 ? independent baselines) Pipeline processing scheme 50 ms time resolution, with 1 s resolution for non-flare data

14. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research14 / 44 Source Morphology Using dual polarization to deduce double source structure Hanaoka (1997)

15. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research15 / 44 Source Morphology Hanaoka (1997) Interacting Loops

16. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research16 / 44 Source Morphology Interacting Loops 29 10 Nishio et al. (1997) Nishio et al. (2000)

17. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research17 / 44 Source Morphology Conclusions Impulsive flares usually show asymmetry (see also Kundu et al. 1995). 17 GHz microwaves may be from loop-top or footpoints, or both Missing from this list are events showing almost no structure (even with 5” restored beam using super-resolution), e.g. 5 events in Kundu, et al. (2001c) FASR’s 1” resolution is needed—will it be enough?

18. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research18 / 44 Dual-Frequency Loops Yokoyama et al. (2002) White et al. (2002)

19. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research19 / 44 Dual-Frequency Loops Kundu et al. (2001c) Models (const B) Models (non-const B) Observations 17 GHz I 17GHz V 34 GHz I

20. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research20 / 44 White et al. (2002) Dual-Frequency Loops

21. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research21 / 44 Additional Model of Dual-f Loops Melnikov et al. (2002)

22. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research22 / 44 Loops and Loop Models Conclusion About half of the “large” loop events observed at 17/34 GHz are brighter near the footpoints (as expected). A significant number have looptop sources, which appears to require anisotropic pitch angles for the injected electrons. We must be more sophisticated in our models to account for even the grossest of characteristics for some events. FASR’s imaging spectroscopy will give more complete loop diagnostics.

23. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research23 / 44 Electron Dynamics (spectral changes) Use morphology to identify magnetic topologyUse morphology to identify magnetic topology Identify mirror pointsIdentify mirror points Model spectral changes (seen with OVSA) to determine electron diffusion parametersModel spectral changes (seen with OVSA) to determine electron diffusion parameters Model pitch-angle diffusion as needed to account for obs.Model pitch-angle diffusion as needed to account for obs. Lee et al. (2000) 17 GHz 10.6 GHz 5.0 GHz

24. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research24 / 44 Electron Dynamics (TOF) Requires high time resolution observations (<1 s)Requires high time resolution observations (<1 s) Do timing at spatially distinct source locationsDo timing at spatially distinct source locations Bastian (1999)

25. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research25 / 44 Electron Dynamics (TOF) Hard X-ray and main 17 GHz source are simultaneousHard X-ray and main 17 GHz source are simultaneous Remote 17 GHz source is delayed by ~500 msRemote 17 GHz source is delayed by ~500 ms Acceleration is near main sourceAcceleration is near main source Speed is 120,000 km/sSpeed is 120,000 km/s Hanaoka (1999)

26. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research26 / 44 from Aschwanden et al. (1992) Type U bursts observed by Phoenix/ETH and the VLA. Particle Trajectories …and Electron Dynamics

27. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research27 / 44 LDE Source Morphology Altyntsev et al. (1999)

28. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research28 / 44 LDE Source Morphology Kundu et al. (2004)

29. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research29 / 44 Imaging Spectroscopy Kundu et al. (2004) Lots of related activity was occurring at the same time, at dm.Lots of related activity was occurring at the same time, at dm. FASR will image sources throughout the entire spectral range.FASR will image sources throughout the entire spectral range. Timing and spatial relationships should allow a detailed understanding of associations if not causal connections.Timing and spatial relationships should allow a detailed understanding of associations if not causal connections.

30. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research30 / 44 from Aschwanden et al. 1996 Energy Release and Particle Acceleration This cartoon shows the general spatial relationships expected for loop sources. FASR will image this entire structure for the first time. Electrons can run, but they cannot hide (G. W. Bush).

31. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research31 / 44 Flare Productivity/Space Weather Long-term observations (Kundu et al. 2001b)Long-term observations (Kundu et al. 2001b) Coronal Heating (White et al. 1995)Coronal Heating (White et al. 1995) Eruptive events (Hori et al. 2000)Eruptive events (Hori et al. 2000) Relation to type II, type III (Nakajima & Yokohama 2002; Aurass et al. 2002)Relation to type II, type III (Nakajima & Yokohama 2002; Aurass et al. 2002)

32. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research32 / 44 Flare Productivity/Space Weather Solar-dedicated instrument can look at long-term flare productivity. Small events (< 10 sfu) in “typical” active region show relaxation of energy buildup, avoiding major flares. Kundu et al. (2001b)

33. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research33 / 44 Flare Productivity/Space Weather Contours show active region, and gray-scale shows location of tiny radio events. FASR will provide magnetic field and temperature maps of the active region, along with full spectroscopic imaging of the events (and at 10 times higher spatial resolution). Radio diagnostics should allow us to track energy release and conversion to heating. Kundu et al. (2001b)

34. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research34 / 44 Flare Productivity/Space Weather Active region transient brightenings (ARTBs) with 17 GHz flux densities < 1 sfu appeared to be consistent with thermal emission. However, Gary et al. (1997) showed that there is plenty of non-thermal microwave emission at lower frequencies. White et al. (1995)

35. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research35 / 44 Flare Productivity/Space Weather Even fainter events are seen outside of active regions, in numbers that may implicate them for heating the corona. FASR will provide counts of such events over the entire disk, and provide additional spectroscopic imaging diagnostics. The sensitivity of FASR to such events is likely to be confusion limited, and it remains to be determined what the flux density limit will be. Krucker et al. (1997)

36. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research36 / 44 Flare Productivity/Space Weather Erupting prominences and other moving features associated with flares. FASR’s higher resolution and multifrequency imaging will allow excellent radio diagnostics. Hori et al. (2000) Gopalswamy

37. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research37 / 44 Flare Productivity/Space Weather Collimated jet associated with type II burst. Nakajima & Yokoyama (2002)

38. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research38 / 44 Flare Productivity/Space Weather Moving 17 GHz feature (5:31-5:33 UT) associated with type II burst. Aurass et al. (2002)

39. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research39 / 44 Nancay CME Movies

40. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research40 / 44 Observed CME Spectrum from Bastian et al. 2001

41. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research41 / 44 How FASR Will Use These Lessons Full Sun (to 17 GHz)Full Sun (to 17 GHz) Solar-dedicated, solar-optimizedSolar-dedicated, solar-optimized 1” resolution (at 20 GHz)1” resolution (at 20 GHz) Excellent imaging/dynamic range (5000 baselines)Excellent imaging/dynamic range (5000 baselines) High time resolution (100 ms)High time resolution (100 ms) Wide, densely sampledfrequency rangeWide, densely sampledfrequency range

42. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research42 / 44 Conclusion FASR is being designed to address an extremely rich range of solar science, utilizing state-of-the-art technology.FASR is being designed to address an extremely rich range of solar science, utilizing state-of-the-art technology. Some aspects of the instrument have yet to be defined, and help is sought in the design, simulations, and software effort.Some aspects of the instrument have yet to be defined, and help is sought in the design, simulations, and software effort. Please help to make FASR an international effort. By working together we can make FASR a truly remarkable facility.Please help to make FASR an international effort. By working together we can make FASR a truly remarkable facility.

43. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research43 / 44 FASR Contacts FASR web page:FASR web page: http:/www.ovsa.njit.edu/fasr/ http:/www.ovsa.njit.edu/fasr/ FASR U.S.: Tim Bastian, Dale Gary, Stephen White, Gordon HurfordFASR U.S.: Tim Bastian, Dale Gary, Stephen White, Gordon Hurford FASR France: Monique Pick, Alain KerdraonFASR France: Monique Pick, Alain Kerdraon

44. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research44 / 44 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)

45. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research45 / 44

46. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research46 / 44 Magnetic Field Spectral Diagnostics 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. Model from Mok et al., 2004; Simulation from Gary et al. 2004

47. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research47 / 44 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 f B = 1 GHz) from Gary et al. 2004

48. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research48 / 44 Coronal Magnetograms Accurate simulation of FASR coronal magnetograms of potential and non- potential active region, and difference compared with current-density map from the model. from Gary et al. 2004

49. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research49 / 44 B l from Free-Free Emission This capability remains speculative, but with sufficient polarization sensitivity, B l can be deduced everywhere down to ~ 20 G using: where n is the spectral index from Gelfreikh, 2004—Ch. 6 from Gary & Hurford, 2004—Chapter 4

50. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research50 / 44 Magnetic Topology from QT Layer 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. from Ryabov, 2004—Chapter 7

51. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research51 / 44 FASR Science Goals (2) Image CMEs both on the disk and off the limbImage CMEs both on the disk and off the limb  Observe non-thermal electrons in CMEs easily  Possibly detect free-free emission in some CMEs  Relate other forms of activity (both thermal and nonthermal) that take place simultaneously, with perfect co-registration  Observe analog of EIT/Moreton waves/coronal dimmings, filaments, type II bursts, and CMEs all in one panoramic view!  No occulting disk! Image CMEs both on the disk and off the limbImage CMEs both on the disk and off the limb  Observe non-thermal electrons in CMEs easily  Possibly detect free-free emission in some CMEs  Relate other forms of activity (both thermal and nonthermal) that take place simultaneously, with perfect co-registration  Observe analog of EIT/Moreton waves/coronal dimmings, filaments, type II bursts, and CMEs all in one panoramic view!  No occulting disk!

52. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research52 / 44 Observed CME Spectrum from Bastian et al. 2001

53. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research53 / 44 Imaging the CME Density Enhancement via Free-Free Early FASR simulation New simulations are underway by Vourlidas and Marque see Vourlidas, 2004— Chapter 11 Image simulated with 73-element array 37 element array from Bastian & Gary 1997

54. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research54 / 44 FASR Science Goals (3) Radio spectral diagnostics of particle acceleration & energy release, with excellent spatial and temporal resolutionRadio spectral diagnostics of particle acceleration & energy release, with excellent spatial and temporal resolution  Directly image energy release region  Follow evolution of electrons from acceleration, through transport, and escape or thermalization  Obtain spectral diagnostics of energy/pitch angle distributions* * see tomorrow’s poster by Lee et al. Radio spectral diagnostics of particle acceleration & energy release, with excellent spatial and temporal resolutionRadio spectral diagnostics of particle acceleration & energy release, with excellent spatial and temporal resolution  Directly image energy release region  Follow evolution of electrons from acceleration, through transport, and escape or thermalization  Obtain spectral diagnostics of energy/pitch angle distributions* * see tomorrow’s poster by Lee et al.

55. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research55 / 44 from Aschwanden et al. 1996 Energy Release and Particle Acceleration Subsecond timescales, with rapid frequency drift over 100s of MHz. The decimetric part of the spectrum has never been imaged.

56. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research56 / 44 Panoramic View Proffered by Radio Emission from Benz, 2004— Chapter 10

57. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research57 / 44 Solar Flare Diagnostics Multifrequency imaging allows spatially resolved spectral diagnostics More complete simulations are now underway, see poster by Lee et al.

58. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research58 / 44 FASR Science Goals (4) Image radio emission from shocks (type II), electron beams (type III), and other bursts over heights 1-2.5 R sImage radio emission from shocks (type II), electron beams (type III), and other bursts over heights 1-2.5 R s  Global view of type II emission (multi- frequency gives multiple plasma layers)  Relate type II to CME, waves, accelerated particles  Follow type III (and U-burst) trajectories throughout frequency, and hence height Image radio emission from shocks (type II), electron beams (type III), and other bursts over heights 1-2.5 R sImage radio emission from shocks (type II), electron beams (type III), and other bursts over heights 1-2.5 R s  Global view of type II emission (multi- frequency gives multiple plasma layers)  Relate type II to CME, waves, accelerated particles  Follow type III (and U-burst) trajectories throughout frequency, and hence height

59. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research59 / 44 EIT Waves and Shocks

60. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research60 / 44 Complete imaging over a wide frequency range that connects solar and IP events. Integrated view of thermal, nonthermal, flare, CME, shocks, electron beams. High Spectral and Temporal Resolution

61. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research61 / 44 from Aschwanden et al. (1992) Type U bursts observed by Phoenix/ETH and the VLA. Particle Trajectories

62. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research62 / 44 Particle Trajectories from Raulin et al. (1996)

63. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research63 / 44 FASR Science Goals (5) Construct 3D solar atmospheric structure (T, B, n e ) over a wide range of heightsConstruct 3D solar atmospheric structure (T, B, n e ) over a wide range of heights  Image individual heated loops  Image filaments, filament channels, eruptions, with spectral diagnostics  Combine radio, EUV, X-ray diagnostics for complete model of 3D structure Construct 3D solar atmospheric structure (T, B, n e ) over a wide range of heightsConstruct 3D solar atmospheric structure (T, B, n e ) over a wide range of heights  Image individual heated loops  Image filaments, filament channels, eruptions, with spectral diagnostics  Combine radio, EUV, X-ray diagnostics for complete model of 3D structure

64. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research64 / 44 Diagnostics of Loop Heating FASR spectra of individually imaged hot loops yield detailed diagnostics from Achwanden et al., 2004—Chapter 12

65. Nobeyama Symposium 2004 Oct 29NJIT Center for Solar Terrestrial Research65 / 44 3D Model Using VLA/SERTS/EIT Model simultaneously fits radio brightness, EUV DEM, temperature and density parameters from Brosius 2004— Chapter 13