Rainer Schwenn Max-Planck-Institut für Aeronomie Katlenburg-Lindau International Solar Cycle Studies 2001 (ISCS), June 13-16, 2001 Longmont, Colorado CME.

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!