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?
??