Rainer SchwennMax-Planck-Institut für Aeronomie
Katlenburg-Lindau
International Solar Cycle Studies 2001 (ISCS),
June 13-16, 2001Longmont, Colorado
CME Mythology: Do Global CMEs or Sympathetic CMEs Exist?
A classical “halo” CME, observed by LASCO-
C2 on 4.11.1998
Towards or away from Earth? That knowledge would grantspace weather predictions a new quality
Halo CMEs: a new quality from SOHO
A pressure wave (EIT Wave) in the solar
atmosphere, pushed by a flare on
7.4.1997.A halo CME was
launched towards Earth that caused a geomagnetic storm
on 10.4.97.
Front or backside: a new quality from SOHO
This CME began as a “global” CME, i.e. in two parts
simultaneously on both limbs. Later, the envelope turned into
a full halo.
Note: the source “axis” was about parallel to the lobes’ axis
Another apparent halo CME, also from two parts on
opposite limbs
This was the obvious source, on the front side.
The bright flash occurred at 05:58 UT, and the axes were parallel.However…
…close inspection of C2 images proves: the east limb event started more than one hour ahead of time! An independent
backside source?
Morale: better look twice, in particular if you are about to create a myth…
No: two lobes contained in one single halo CME, a “split halo”
The typical “global” CME?
The same event: the source axis was
perpendicular to the lobes’ axis!
No “global “ event, just two lobes contained in a halo CME, a backside event by the way
Another split halo CME, “butterfly type”
In this “butterfly type” halo CME,the axis was about 450 off
2 lobes under a common halo envelope.The source was oriented almost parallel to the lobes’
axis.
The source axis is perpendicular
to the lobes’ axis
One more example: a “butterfly-type” halo CME, on the backside
A perfect halo, originating close to to disc center
A halo CME, “cannibalizing” a limb
CME
Close relatives of “global” CMEs: Cannibals!
Gopalswamy, 2000
A halo CME, “cannibalizing” a limb
CME
Close relatives of “global” CMEs: Cannibals!
Note: the “light bulb” CME had occurred behind the limb
Gopalswamy, 2000
2 succeeding halo CMEs, “cannibalizing” a
limb CME
Close relatives of “global” CMEs: Cannibals!
Gopalswamy, 2000
Suggestion: “…the chains are visible manifestations of separators or quasi-separatrix layers formed between different interacting
large-scale magnetic flux systems in the evolving global magnetic solar atmosphere”
Chertok, 1997 ff
Other suspects in context with global CMEs: magnetic chains
Bothmer and Schwenn, 1998
Sketch showing the possible large-scale topologyof a flux-rope magnetic cloud
Alternative explanation of “global” CMEs:
new perspective on flux ropes
Erupting flux rope with its legs connected to the sun
Alternative explanation of “global” CMEs:
new perspective on flux ropes
Chen et al., 1993 ff
This CME (on September 9th, 1997) was well observed by the Mark 3 and LASCO coronagraphs. It fits well to the erupting flux rope
model
Chen et al., 2000
This is what the flux rope model would predict how this CME should look like
Chen et al., 2000
1. A typical flux rope CME seen from the side, I.e. above one limb
Different perspectives of flux rope CMEs
2. An extended flux rope CME seen from the front or
back side. Note the 2D rope structure and the engulfing 3D halo
CME structure.
“Global” CMEs:
a projection
effect!
“Global” CMEs:
a projection
effect!
Rainer SchwennMax-Planck-Institut für Aeronomie
Katlenburg-Lindau
CME Mythology: Do Global CMEs or Sympathetic CMEs Exist?
My answer is: No.
They are probably just head-on (or head off…?) flux rope halo CMEs. Let’s see what they look like from
different perspectives, i.e., STEREO and Solar Orbiter.
STAY TUNED!
