Solar Cycle 24 Group F
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with stereo - we can see these are not backsided. | with stereo - we can see these are not backsided. | ||
| + | obvious controversy suggest we are a lonf way from solving | ||
| + | -different people see different conclusions from the same data! | ||
Revision as of 02:29, 10 December 2008
Contents |
Tuesday 9th Dec
Introduction 14:30 - 16:00
STERLING Earliest phases of solar eruptions
preflare phase & trigger mechanism for filaments as tracer of B field, slow rise -> flare + fast rise
few (12) example event studied. 2 may 2007, TRACE & HINODE, good example.
filaments undergo slow rise (few km/s), then fast. the slow rise is linear then flare at start of fast eruption. could be some signatures of 'breakout'
dimmings - local (near neutral line) or remote (associated with breakout?)
QUESTIONS ARISING:
how common is a slow rise?
what triggers slow & fast rise phases?
where to go from here? Clearly Hinode and SECCHI 171 2 min cadence? so synoptic data modes are fine for this project?
ATRILL Coronal waves and dimmings
EIT waves map the CME footpoints? Angelos -mixing lateral mass expansion & wave? Atrill - the expansion of CME stops when wave stops.
Explains the brightnenings at the CME legs
WD - Tunnelling of waves into coronal hole?
Dimmings: could be evacuation or cooling also agree with deep core and secondary dimmings
Mass measurements from plasma outflows?
Angelos: No brightenings in 304, so not reconnection? McAteer: reflection and refraction problem?
Attril: does not mean there is no wave, the CME footpoints could cause a wave?
why/how do CD disappear while magnetic connectivity of the CME ejecta to Sun is maintained? recovery can be due to Interchange reconnection.
reconnection rate at same speed as the wave? 0.1 X 0.2 alfven speed - too low?
expansion of cme flanks should correspond with eit wave speed.
MCATEER CME Kinematics
–Kinematics is the study of the motion
–Energetics is the study of the forces which cause the motion.
•What forces govern the propagation?
•What forces govern the expansion?
from height time profiles -> acceleration profiles
• What are we tracking?
- image to image,
- event to event,
- study to study
• Can we reduce the errors?
• Are we capturing the full profile?
- What about lower down?
combine with mass -> work done, force and power.
Known Knowns
•Well characterized and large sample studies from 3-30RSUN
•Well developed techniques to study energetics and kinematics
Known Unknowns
•Behaviour at 1-3RSUN and greater than 30RSUN
•Even at 3-30RSUN,
–where do the forces act and over what distance?
–when do the forces act and over what timescale?
Unknown Unknowns?
-What is the initiation mechanism?
-What is the CME - flare/filament link?
-The ever-illusive current sheet - any other choice?
from stereo - better H-T low down, and multi direction.
more automated tracking.
STEED locating the solar source
ICME ejecta - components of ICME show a left -handed cloud (-ve helicity)
launch window determined - 80hours before, roughly noon 10-april 2006 no obvious cme signatures (flares, dimmings, etc) survey possible launch regions.
search for source region with -Ve helicity. only one possible no erupting filaments, or possible cmes (because of lack of launch, conclude a back-sided event)
find some evidence of cusp shaped loop - > eruption signature? without vector data- cannot rule out helicity problems.
WHAT WILL WE LEARN?
HOWARD source regions A skeptics view of flare-cme relationship
how do we define a flare and a cme cme- outward propagation of brightness enhancement in WLC flare - brightening in cr, tr or coronal emmisison
associating lists is dangerous all current theories have a flare as necessary consequence of eruption, but not neccesaary cause and effect.
There are CME without flares -called backside, faint flare (not in GOES) there are cmes which have no chromospheric signatures - 'streamer blowout'
with stereo - we can see these are not backsided.
obvious controversy suggest we are a lonf way from solving -different people see different conclusions from the same data!
Events 17:00-18:30
