Flare waves and the impulsive phase

H. S. HudsonSpace Sciences Laboratory

University of California, Berkeley

Berkeley 2/2/10

Global Waves

• Interplanetary shock (SSC)*; Type II burst; Moreton wave; seismic wave

• Major controversy on the interpretation of the metric type II and Moreton wave: is it a blast wave (two-wavism) or is it a CME-driven bow shock (one-wavism)?

• The Uchida (1968) theory unified the global waves in the corona. How do the interior seismic wave fit in?

*Storm Sudden Commencement

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The “impulsive” phase

• Synchrotron radiation and hard X-ray bremsstrahlung

• Deep atmospheric effects (the UV/WL/IR emission)

• Non-thermal signatures

• The Neupert effect:

The “impulsive” phase

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Benz, 2002 http://sprg.ssl.berkeley.edu/~tohban/browser

The Carrington Flare, 1859

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(Chapman & Bartels)

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(Chapman & Bartels)

The Carrington Flare, 1859

Moreton Wave 6 Dec. 2006

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1844 UT

The wave appears near the peak of the impulsive phase of the high-energy flare …

Kaufmann et al. (2008)

Metric type II burst

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freq

uenc

y

time

• Slow drift to low frequencies• Plasma frequency• Shock acceleration of e-

Global wave seen in STEREO

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Seismic waves schematic

Photosphere

Interior

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Seismic Wave, 9 July 1996

(Kosovichev & Zharkova 1997)

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Seismic Wave, 15 January 2005

(Moradi et al. 2007)

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The same temporal filter applied to the white-light emission and acoustic source

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Comparison of wave energies*

• IP shock: ~10% (Mewaldt)• Moreton wave: >10-4 (Gilbert)• Seismic wave: ~10-4 (Lindsey)

*based on CME = flare = 1 (Emslie et al. 2005)

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Magnetic changes during flares

“Confusogram” legend: 10x10 2.5” pixels 240 minutes time base 500 G magnetic range

(Sudol & Harvey 2005)

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TRACE: dimming, implosion, oscillations

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Wave tracing

• The Huyghens principle is necessary and sufficient (Wills-Davey & Thompson et al. 1999)

• Using it we can track either coronal or seismic waves back to the source

• The holographic technique works well for seismic waves

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Flare/CME timing

Zarro et al 1999 Zhang et al 2001

Dimming CME speed vs time

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Flare energy

Woods et al 2004

Hudson et al 2006

In time In space

Cartoons

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Hudson 2000Welsch 2008

Fletcher & Hudson 2008Liu et al. 2007http://solarmuri.ssl.berkeley.edu/~hhudson/cartoons

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Wave origins

• The coronal wave could be either a blast wave (Uchida) or else a CME bow wave

• The origin of the coronal wave could be either in a pressure pulse, or via the Lorentz force

- n.b. the corona has low plasma beta• The seismic wave requires momentum transfer at or

below the photosphere• “…CMEs display an impulsive acceleration phase that

coincides very well with the flare’s rise phase…” (J. Zhang et al., 2001)

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CMEless X-class flare

Gopalswamy et al. 2009

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CMEless X-class flares

Gopalswamy et al. 2009

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LASCO shock signatures

Ontiveros & Vourlidas. 2009

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1999 April 2

Examples from Vourlidas et al. 2003

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Coronal waves

• CMEless flares have an upper cutoff in energy, implying environmental control of CME occurrence

• The CME acceleration phase matches the flare impulsive phase

• The lack of type II bursts with CMEless X-class flares implies that the Uchida-type wave is too weak

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An interesting problem in mathematical physics?

• In Uchida theory, the coronal blast wave refracts into the chromosphere to produce the Moreton wave

• In the CME bow shock configuration, this physics is different and needs to be worked out

- The math may have been done by Kelvin, but it is not easy to identify in modern literature

• The problem: How do we understand the transport of energy along the flanks of the coronal bow shock?

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Conclusions

• Coronal and seismic waves originate in the impulsive phase of a flare

• A CME (ie, unconstrained perpendicular outflow) is necessary for the generation of a coronal wave

• The waves in general illuminate the nature of the flare/CME restructuring

• There are some theoretical problems

- behavior of shock flanks

- conjecture on vector field change

Slides nobody needs to see

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Seismic Wave, 29 October 2003

(Donea & Lindsey 2005)

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Subtracted Doppler Images (R-B Wing) Showing Down-Up Pattern

18:44 UT 18:47 UT

18:50 UT 18:52 UT