Imaging Solar Coronal Structure With TRACE Leon Golub, SAO TRACE: ISAS - 4 Feb. 2003.

Imaging Solar Coronal Structure With TRACE

Leon Golub, SAO

TRACE:http://vestige.lmsal.comTRACE:http://vestige.lmsal.com

ISAS - 4 Feb. 2003

The SAO Solar-Stellar X-ray Group

• Leon Golub• Jay Bookbinder• Ed DeLuca• Mark Weber• Joe Boyd• Paul Hamilton• Dan Seaton• With results from A. Van Ballegooijen, A. Winebarger

and H. Warren

http://hea-www.harvard.edu/SSXG/http://hea-www.harvard.edu/SSXG/

The Major Coronal Physics Problems

1. Why is the corona hot?

2. Why is the corona structured?

3. Why is the corona dynamic & unstable?

Emergence of B into the atmosphere,

and response to B.

Why Use X-rays to Observe Corona?

Heating & Dynamics in ARs

TRACE sees four (or possibly only three)distinct processes in active regions:

1. Steady outflows in long, cool structures. ◄

2. Transient loop brightenings in emergingflux areas. Also hot & cool material intertwined –May or may not be related to TLBs.3. Steady heating of hot loops (moss). ◄4. Flare-like events at QSLs (or may be coolingevents predicted by 3.).

Examples of all four

phenomena

Another example of flows

11

TRACE Active Region Observations are not Consistent With Hydrostatic Model

Figure from Aschwanden et al. 2000

12

Non-HS Loops are ubiquitous

courtesy H. Warren

Partial Listing of Recent Papers About Non-Hydrostatic Loops

• Lenz etal 1999, ApJ, 517, L155.• Aschwanden etal 2000, ApJ, 531,

1129.• Winebarger etal 2001, ApJ, 553,

L81.• Schmelz etal 2001, ApJ, 556, 896.• Chae etal 2002, ApJ, 567, L159.• Testa etal 2002. ApJ, 580, in press.• Martens etal 2002, ApJ, 577, L115.• Schmelz 2002, ApJ, 578, L161.• Aschwanden 2002 ,ApJ, 580, L79.• Warren etal 2003, ApJ, submitted.

• Small gradient in filter ratio, high n. • Multithread model (a la Peres etal 1994, ApJ

422, 412), footpoint heating.• Flows and transient events in non-hydrostatic

loops.• DEM spread → const. filter ratio.• More passbands may help.• Large range in thread T for some loops. • Full DEM need at each point.

• Grad T along loops w/flat filter ratio• Contra Martens.• Repeated heating episodes.

What Needs to be Explained?

• 1. 195A/173A ratio is flat.

• 2. Emission extends too high for hydrostatic loop (this is debated, though).

• 3. Loop density is high by an order of magnitude.

• 4. Apparent flows (and some Doppler shifts measured).

Active Region 8536

How isothermal are these loops?

17

SUMER Velocities

Symmetric vs. Asymmetric Heating

Static vs. Flow Model

Winebarger etal ApJL (2001)Winebarger etal ApJL (2001)

High-Conductance Model withAsymmetric Heating

The Effect of High Conductivity

Footpoints in Transient Heating

1. Initial energyrelease alongcurrent sheet(“spotty”)

2. Footpooint brightening.

3. Evaporation,then post-flareloops.

Comparison: Evaporative Model vs.TRACE Obs.

Moss as TR of Hot Loops

Heating Shut-off vs. Observations

Hot Material in the Corona

Mg XII Ly-αsuperposed onFe X (log T =6.9 and 6.0)

Consistent with RHESSIdetection of non-thermalelectrons in “quiescent”active regions.

END PRESENTATION

March 17, 2000 M1.1: TRACE 1600 Å Movie

Warren & Warshall,ApJL (2001)Warren & Warshall,ApJL (2001)

March 17, 2000 M1.1: TRACE 1600 Å Images

March 17, 2000 M1.1: TRACE 1600 Å Light Curves

TRACE Footpoint vs. BATSE HXR

→HESSI!

The Solar-B Mission

The Solar-B Instrument Complement

1. Solar Optical Telescope with Focal Plane Package (FPP)- 0.5m Cassegrain, 480-650nm- VMG, Spectrograph- FOV 164X164 arcsec

2. EUV Imaging Spectrograph (EIS)- Stigmatic, 180-204, 240-290Å- FOV 6.0X8.5 arcmin

3. X-ray Telescope (XRT)- 2-60Å- 1 arcsec pixel- FOV 34X34 arcmin

XRT vs. SXT Comparison

1. Higher spatial resolution: 1.0” vs. 2.5”

2. Higher data rate: 512kB continuous.

3. Ten focal plane analysis filters.

4. Extended low-T and high-T response.

5. FIFO buffer for flare-mode obs.

October 24, 2001 XRT CDR Overview/Systems* P. Cheimets-1

Solar-B XRT Flight Design

Front Door andHinge Assembly

Electrical Box

Ascent Vent2 places

Graphite Tube Assembly

Camera

Feed-ThruElectrical

65

Science Themes

• Plasma Dynamics• Thermal Structure and Stability• The Onset of Large Scale Instabilities• Non-Solar Objects

66

Plasma Dynamics

• Reconnection– loop-loop interaction

– flux emergence

– nano-flares

– AR jets

– macro-spicular jets

– filament eruption

67

Plasma Dynamics• Waves

– origin of high speed wind

– tube waves

– coronal seismology

Figures from Nakariakov et al. (1999): decaying loop oscillations seen in TRACE can be used to estimate the coronal dissipation coefficient.

Re ~ 6 x 105 or Rm ~ 3 x 105 , about 8 orders of magnitude less than classical values.

68

Thermal Structure/Stability

• Physical Properties– Te, ne, EM

– energetics

– variability timescales

• Multithermal Structure– steady loops

– filaments

69

Onset of Large Scale Instabilities

• Emerging Flux Region– twisting/untwisting

– reconnection

• delta Spots– current sheets

– topology changes

• Active Filaments– Te, ne

– local heating

70

Non-Solar Objects

• Jupiter

– S VII @ 198

• Nearby RS Cvns

• Galaxy Cluster Halos

• Comets

• Any EUVE source within 1 deg of Sun

Science Drivers I: Spatial Scales• “Global” MHD Scales

– Active Regions; – granulation scales

• Transverse scales

n

B and j

• Reconnection sites– location– size– dynamics

105 km

103 km

101 - 103 km

<10 km

<10 km

RAM discoveryspace

Science Drivers II: Time Scales• Loop Alfven time

• Sound speed vs. loop length

• Ion formation times

• Plasma instability times

• Transverse motions

• Surface B evolution times

• ~10 sec

• ~100 sec

• ~1 - 10 sec

• ~10 - 100 sec

• 1 - 100 sec

• minutes - months

Optics Metric