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

Nobeyama Symposium 2004 Oct 29 NJIT Center for Solar Terrestrial Research 1 / 44

FASR Flare Science: Lessons from the Nobeyama Radioheliograph

Dale E. Gary

New Jersey Institute of Technology


Outline

• The FASR conceptThe FASR concept

• The NoRH specifications that are The NoRH specifications that are important for flare researchimportant for flare research

• What we have learned about flares from What we have learned about flares from NobeyamaNobeyama

• How FASR will use these lessonsHow FASR will use these lessons


FASR Instrument (Antennas)

Three arrays, 6 km baselines (<1” at 20 GHz)Three arrays, 6 km baselines (<1” at 20 GHz)

Array Designation

Number of Antennas

Frequency Range

Antenna Size

FASR-A High Frequency Array

~100 2-24 GHz 2 m

FASR-BLow Frequency Array

~60 0.2-3 GHz 6 m

FASR-CLog-Periodic Dipole Array

~40 20-300 MHzLog-

dipole



FASR Instrument (Receivers)

Broadband RF transmission, Digital FX CorrelatorBroadband RF transmission, Digital FX Correlator

Quantity Spec

Frequency Resolution0.1% (FASR-C)

1% (FASR-A,B)

Time Resolution10 ms (FASR-B,C)

100 ms (FASR-A)

Polarization Stokes IV (QU)

Instantaneous Bandwidth ~1 GHz


FASR Signal Path

Correlator and DSP

12-bitDigitizer

Analog fiber-optic cable

On-lineCalibration

Data Storage

LAN

Internet

Burstmonitor(s)

RFImonitor(s)

RF Converter Room IF Processor Room

Control Room

RF-IFconverter

Bac

k-en

d

LOdistribution

Polyphase Filter Bank

1-bit Sampler

Front-end

Element

Com

puti

ng

Sys

tem

From other

antennas


FASR-A


FASR-B,C


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)


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)


FASR Science GoalsFASR Science GoalsDesigned 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. Directly measure coronal magnetic fields2. Image Coronal Mass Ejections (CMEs)3. Obtain radio spectral diagnostics of particle

acceleration / energy release, with excellent spatial and temporal resolution

4. Image radio emission from shocks (type II), electron beams (type III), and other bursts over heights 1-2.5 Rs

5. Construct 3D solar atmospheric structure (T, B, ne) over a wide range of heights


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


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


Source MorphologySource MorphologyUsing dual polarization to deduce double source structureUsing dual polarization to deduce double source structure

Hanaoka (1997)Hanaoka (1997)


Source MorphologySource Morphology

Hanaoka (1997)

Interacting LoopsInteracting Loops


Source MorphologySource MorphologyInteracting LoopsInteracting Loops

2 9

10Nishio et al. (1997)Nishio et al. (1997)

Nishio et al. (2000)Nishio et al. (2000)


Source MorphologyConclusions• 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?


Dual-Frequency LoopsDual-Frequency Loops

Yokoyama et al. (2002)White et al. (2002)


Dual-Frequency Loops

Kundu et al. (2001c)

Models (const B)

Models (non-const B)

Observations17 GHz I 17GHz V 34 GHz I


White et al. (2002)

Dual-Frequency Loops


Additional Model of Dual-f Loops

Melnikov et al. (2002)


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.


Electron Dynamics (spectral changes)Electron Dynamics (spectral changes)• Use morphology to identify Use morphology to identify

magnetic topologymagnetic topology• Identify mirror pointsIdentify mirror points• Model spectral changes (seen Model spectral changes (seen

with OVSA) to determine with OVSA) to determine electron diffusion parameterselectron diffusion parameters

• Model pitch-angle diffusion as Model pitch-angle diffusion as needed to account for obs.needed to account for obs.

Lee et al. (2000)

17 GHz 10.6 GHz 5.0 GHz


Electron Dynamics (TOF)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)


Electron Dynamics (TOF)Electron Dynamics (TOF)• Hard X-ray and Hard X-ray and

main 17 GHz main 17 GHz source are source are simultaneoussimultaneous

• Remote 17 GHz Remote 17 GHz source is delayed source is delayed by ~500 msby ~500 ms

• Acceleration is Acceleration is near main sourcenear main source

• Speed is 120,000 Speed is 120,000 km/skm/sHanaoka (1999)


from Aschwanden et al. (1992)

Type U bursts observed by Phoenix/ETH and the VLA.Type U bursts observed by Phoenix/ETH and the VLA.

Particle TrajectoriesParticle Trajectories…and Electron Dynamics


LDE Source MorphologyLDE Source MorphologyAltyntsev et al. (1999)Altyntsev et al. (1999)


LDE Source Morphology

Kundu et al. (2004)


Imaging SpectroscopyImaging Spectroscopy

Kundu et al. (2004)

• Lots of related activity Lots of related activity was occurring at the was occurring at the same time, at dm same time, at dm ..

• FASR will image FASR will image sources throughout sources throughout the entire spectral the entire spectral range.range.

• Timing and spatial Timing and spatial relationships should relationships should allow a detailed allow a detailed understanding of understanding of associations if not associations if not causal connections.causal connections.


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).


Flare Productivity/Space WeatherFlare Productivity/Space Weather

• Long-term observations (Kundu et al. Long-term observations (Kundu et al. 2001b)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 & Relation to type II, type III (Nakajima & Yokohama 2002; Aurass et al. 2002)Yokohama 2002; Aurass et al. 2002)


Flare Productivity/Space WeatherFlare 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)


Flare Productivity/Space WeatherFlare 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)


Flare Productivity/Space WeatherFlare 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)


Flare Productivity/Space WeatherFlare 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)


Flare Productivity/Space WeatherFlare 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



• Collimated jet associated with type II burst.

Nakajima & Yokoyama (2002)



• Moving 17 GHz feature (5:31-5:33 UT) associated with type II burst.

Aurass et al. (2002)


Nancay CME Movies


Observed CME SpectrumObserved CME Spectrum

from Bastian et al. 2001


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 Excellent imaging/dynamic range (5000 baselines)baselines)

• High time resolution (100 ms)High time resolution (100 ms)

• Wide, densely sampledWide, densely sampled frequency frequency rangerange


ConclusionConclusion• FASR is being designed to address an FASR is being designed to address an

extremely rich range of solar science, utilizing extremely rich range of solar science, utilizing state-of-the-art technology. state-of-the-art technology.

• Some aspects of the instrument have yet to be Some aspects of the instrument have yet to be defined, and help is sought in the design, defined, and help is sought in the design, simulations, and software effort.simulations, and software effort.

• Please help to make FASR an international Please help to make FASR an international effort. By working together we can make FASR effort. By working together we can make FASR a truly remarkable facility.a truly remarkable facility.


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, FASR U.S.: Tim Bastian, Dale Gary, Stephen White, Gordon HurfordStephen White, Gordon Hurford

• FASR France: Monique Pick, Alain FASR France: Monique Pick, Alain KerdraonKerdraon


FASR EndorsementsFASR Endorsements2001 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)



Magnetic Field Spectral DiagnosticsMagnetic Field Spectral Diagnostics

• Model spectra along 2 Model spectra along 2 lines of sight: lines of sight: aa) negative polarity ) negative polarity sunspot, sunspot, bb) positive ) positive polarity sunspot.polarity sunspot.

• The coronal The coronal temperature and the temperature and the magnetic field strength magnetic field strength can be read directly can be read directly from the spectra.from the spectra.

Model from Mok et al., 2004;

Simulation from Gary et al. 2004


2D Magnetogram2D Magnetogram• BB map deduced map deduced

from 1—24 GHz from 1—24 GHz spectra (spectra (bb) match ) match the model (the model (aa) very ) very well, everywhere well, everywhere in the region. (in the region. (cc) ) is a comparison is a comparison along a line along a line through the center through the center of the region.of the region.

• The fit only works The fit only works down to 119 G down to 119 G (corresponding to (corresponding to ff = 3 = 3 ffBB = 1 GHz) = 1 GHz)

from Gary et al. 2004


Coronal MagnetogramsCoronal Magnetograms Accurate Accurate

simulation of simulation of FASR coronal FASR coronal magnetograms of magnetograms of potential and non-potential and non-potential active potential active region, and region, and difference difference compared with compared with current-density current-density map from the map from the model.model.

Accurate Accurate simulation of simulation of FASR coronal FASR coronal magnetograms of magnetograms of potential and non-potential and non-potential active potential active region, and region, and difference difference compared with compared with current-density current-density map from the map from the model.model.

from Gary et al. 2004


Bl from Free-Free Emission• This capability This capability

remains remains speculative, but speculative, but with sufficient with sufficient polarization polarization sensitivity, sensitivity, BBll can can

be deduced be deduced everywhere down everywhere down to ~ 20 G using:to ~ 20 G using:

where where nn is the is the spectral indexspectral index

from Gelfreikh, 2004—Ch. 6from Gary & Hurford, 2004—Chapter 4


Magnetic Topology from QT Layer• Upper panels show Upper panels show

radio “depolarization radio “depolarization line” (DL) at a single line” (DL) at a single frequency due to mode-frequency due to mode-conversion at a quasi-conversion at a quasi-transverse (QT) layer, transverse (QT) layer, vs. photospheric neutral vs. photospheric neutral line (NL).line (NL).

• Using FASR’s many Using FASR’s many frequencies, a QT frequencies, a QT surface can be mapped surface can be mapped in projection. The in projection. The surface changes greatly surface changes greatly with viewing angle. with viewing angle.

from Ryabov, 2004—Chapter 7


FASR Science Goals (2)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!


Observed CME SpectrumObserved CME Spectrum

from Bastian et al. 2001


Imaging the CME Density Enhancement via Free-Free

• Early FASR Early FASR simulationsimulation

• New simulations New simulations are underway by are underway by Vourlidas and Vourlidas and Marque Marque

see Vourlidas, 2004—see Vourlidas, 2004—Chapter 11Chapter 11

Image simulated with Image simulated with73-element array 37 element array from Bastian & Gary 1997


FASR Science Goals (3)FASR Science Goals (3)• Radio spectral diagnostics of particle Radio spectral diagnostics of particle

acceleration & energy release, with acceleration & energy release, with excellent spatial and temporal resolutionexcellent 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 Radio spectral diagnostics of particle acceleration & energy release, with acceleration & energy release, with excellent spatial and temporal resolutionexcellent 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.


from Aschwanden et al. 1996



Subsecond timescales, with rapid frequency drift over 100s of MHz.

The decimetric part of the spectrum has never been imaged.

Subsecond timescales, with rapid frequency drift over 100s of MHz.

The decimetric part of the spectrum has never been imaged.


Panoramic View Proffered by Radio Emission

from Benz, 2004—Chapter 10


Solar Flare DiagnosticsSolar Flare DiagnosticsMultifrequency imaging allows spatially resolved spectral diagnostics

Multifrequency imaging allows spatially resolved spectral diagnostics

More complete simulations are now underway, see poster by

Lee et al.


FASR Science Goals (4)FASR Science Goals (4)• Image radio emission from shocks (type Image radio emission from shocks (type

II), electron beams (type III), and other II), electron beams (type III), and other bursts over heights 1-2.5 bursts over heights 1-2.5 RRss

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 Image radio emission from shocks (type II), electron beams (type III), and other II), electron beams (type III), and other bursts over heights 1-2.5 bursts over heights 1-2.5 RRss

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


EIT Waves and ShocksEIT Waves and Shocks


Complete imaging over a wide frequency range that connects solar and IP events.

Integrated view of thermal, nonthermal, flare, CME, shocks, electron beams.

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

High Spectral and Temporal Resolution


from Aschwanden et al. (1992)

Type U bursts observed by Phoenix/ETH and the VLA.Type U bursts observed by Phoenix/ETH and the VLA.

Particle TrajectoriesParticle Trajectories


Particle Trajectories

from Raulin et al. (1996)


FASR Science Goals (5)FASR Science Goals (5)• Construct 3D solar atmospheric structure Construct 3D solar atmospheric structure

((TT, , BB,, n nee) over a wide range of heights) 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 Construct 3D solar atmospheric structure ((TT, , BB,, n nee) over a wide range of heights) 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


Diagnostics of Loop Heating FASR FASR

spectra of spectra of individually individually imaged hot imaged hot loops yield loops yield detailed detailed diagnosticsdiagnostics

from Achwanden et al., 2004—Chapter 12


3D Model Using VLA/SERTS/EIT• Model Model

simultaneously simultaneously fits radio fits radio brightness, brightness, EUV DEM, EUV DEM, temperature temperature and density and density parametersparameters

from Brosius 2004—Chapter 13

Documents

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