Flare energy and fast electrons via Alfvén waves H. S. Hudson & L. Fletcher SSL/Berkeley and...

Flare energy and fast electrons via Alfvén waves

H. S. Hudson & L. Fletcher

SSL/Berkeley and Glasgow U.

Predictions for Hinode/SOT flare observations

Kosugi memorial, April 27 2007

GONG

SOHO/MDI

BLOS Maps BLOS Maps

Sudol & Harvey (2005), X10 flare of 2003 Oct. 29


Flare of 2001 Aug. 25GONG + TRACE 1600A

Other examples withGOES times

The changes are stepwise, of order10% of the line-of-sight field, andprimarily occur at the impulsive phase of the flare


Replacing the thick-target model

• Large-scale restructuring => flare energy

• Energy transport by Alfvén-mode waves, not electrons

• The “jerk” as an alternative source of seismic waves

Fletcher & Hudson 2007

QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture.


Unknowns in the new scenario

• The partition of flare energy release into Alfvén mode and fast mode is unknown

• There are clear possibilities for electron acceleration not involving beams, but little development in the literature

• The role of fast-mode waves is not so evident in 3D, but mode conversion guarantees their presence


High Alfvén speeds

• Solar astronomers (those not familiar with radio astronomy?) commonly underestimate active-region field strengths and Alfvén speeds

• vA = 3 x 104 km/s is certainly possible (500 G, 109 cm-3)

• The condition < me/mp is also certainly possible, hence inertial Alfvén waves


The McClymont “jerk”

• Yohkoh and Mees observations of rapid sunspot motion during the flare of 15 Nov. 1991

• Estimate of jerk penetration depth of 1.2 Mm in 4 min

• Energy coupling estimated at 3x1029 to 2x1030 ergs

Anwar et al., Solar Phys. 147, 287 (1993)


Predictions of Hinode B variation(B => B+b during flare)

• Coronal implosion (Hudson 2000)• Iz = constant (Melrose) - Difference field b is potential - Ampere’s law integral is an easy test• Conjugate McClymont jerks


Electrodynamics of the collapsing trap

• Betatron acceleration

• Fermi acceleration

• Inductive energy release via chromospheric “electrojet”


Whose ideas to follow?

Obayashi 1975 Hirayama 1974


A more physically correct flare theory

• Obayashi (1975) and Hudson (2000) got it right: A flare represents a collapse of the stressed coronal field

• Flare theories must incorporate the full tensor conductivity in the chromosphere

• The role of reconnection has been greatly overstated

• We do not need a “black box” electron accelerator in the corona; the energy transport is via Alfvén waves instead


Conclusions

• The pattern of field changes may make it possible to identify the physics of flare causation and energy supply

• The “McClymont Jerk” could play a role in launching flare seismic waves

• We should encourage research related to the Hinode observations of before/after vector fields, both theoretical and observational


End

Thanks for discussion and input: George Fisher, Bernhard Kliem, Brian Welsch…


Death to the thick target

• Spatial scales have become very small and make extreme requirements

- extreme particle distribution functions

- strong self-field

- “number problem”

• The “dentist’s mirror” of albedo shows no significant X-ray directivity

• The occurrence distribution of >100 keV events shows no significant directivity


H. Wang, 1993(cf. Anwar et al., 1993)

First clear evidence for flare-associated field changes?


Giovanelli (1948)Gold & Hoyle (1961)

Longcope & Noonan (2000)Anzer & Pneuman (1982)

A Cartoon

Sampler

http://solarmuri.ssl.berkeley.edu/~hhudson/cartoons/

Priest & Milne (1980)

Hudson (2000)

Liu et al. (2005)


Courtesy Török & Kliem

Notes: (1) This simulation shows a kink instability.(2) The simulation has no realistic chromosphere, so the current

patterns are merely illustrative at this time.(3) The simulation does not connect one equilibrium state with

another.

QuickTime™ and aGIF decompressor

are needed to see this picture.

Flare energy and fast electrons via Alfvén waves H. S. Hudson & L. Fletcher SSL/Berkeley and...

Documents

Transcript of Flare energy and fast electrons via Alfvén waves H. S. Hudson & L. Fletcher SSL/Berkeley and...