Energy partition during initial stages of the CME

Jiong Qiu

Physics Department, Montana State University

Outline:

Outstanding issues Recent progress Difficulties

Outstanding issues on energy:

energy storage:

is there enough energy?

how is this energy stored? energy release:

initiation (trigger) of energy release

the form of energy release:

kinetic + potential => CMEs (ECME)

radiative => flares (Eflare)

order-of-magnitudely: ECME ~ Eflare ~ 1029-32 ergs

Flares and CMEs: statistics

related or not?

- fast CMEs are associated with major flares …

how?

- different manifestations of same process

- not a causal relationship

energy?

- qualitative relation between energy proxies

Progress: what we know so far?

308 CME-Solar Microwave Burst events from 1996-2001

CMEs (LASCO) vs SMBs (RSTN) (Dougherty et al. 2002)

CME speed (km/s)

SM

B p

eak

flux

(sfu

)

(Vrsnak et al. 2005)

CME velocity(LASCO)

vsSXR Intensity(GOES 1-8A)

CME kinematic energy (proxy)

vsSXR Intensity

546 CME-flare events from 1996-2001C

ME

sp

eed

CM

E e

ner

gy

time integrated SXR intensity

Flares and CMEs: some more details

CME velocity

flareSXR

The relationship between some flares and CMEs may be closer than we had thought, thus the energy partition becomes a valid question.

closely related CME motion and flare emission in some well observed events (Zhang et al. 2001)

Flares and CMEs: possible link

electric field (V/cm)flux rate (1018 Mx/s)

Correlated CME/filament acceleration and magnetic reconnection rate

11 12 13 14

C EC

flare emission Correlated flare non-thermal emission (energy release rate) and magnetic reconnection rate.

in a single event

CME speed, mass, and kinetic energy may be scaled with the total reconnection flux.

Flares and CMEs: possible link

total reconnection flux (1021 Mx)

speed mass k. energy

Vcme~ r0.27 Mcme~ r

0.39 Kcme~ r0.89

in a group of events

flare radiation, CME kinematic energy, and reconnection flux in a number of events: with or without filament eruptions in a variety of magnetic configurations in source regions

Flares and CMEs: energy?

total reconnection flux (1021 Mx)

SXR flux

Fflare ~ r1.17 Kcme~ r

0.89

CME k. energy

Harrison (1995) “…the flare and CME are signatures of the same magnetic ‘disease’, that is, they represent the responses in different parts of the magnetic structure, to a particular activity; they do not drive one another but are closely related.”

Reconnection governs energy release in flares.

Reconnection restructures the magnetic configuration in such a way that enhances the upward force thus acceleration, or the other way around.

Summary: what do we think we know?

flare <==> magnetic reconnection <==> CME

Reconnection governs energy release in flares.

Relationship between reconnection rate and energy release rate is not known.

Converting radiation power to energy

release rate is difficult.

Difficulties: what we do not know?

reconnection and CME acceleration

it crucially depends on the relevant magnetic

structures and evolution, which are not directly

observable.

- magnetic structure of CMEs

- ambient magnetic field

- how is the CME structure formed: e.g. pre-

existing and reconnection formed flux rope

r - p: reconnection flux and twisted flux in flux ropes

linearly scaled comparable no bimodal pattern w/ or w/o erupting filament

P - r quite relevant flux rope largely in- situ formed?

(Qiu et al. 2007)

Hu et al. 02

Leamon et al. 04

Lynch et al. 05

Flare <==> CME

Correlated events: selection effect? size effect?

Not correlated events: different mechanisms? a fat “end” of continuous distribution?

??