Chen, James and Jonathan Krall, Acceleration of coronal mass ejections, Journal of Geophysical Research (Space Physics), 108, 1410 (2003) (ADS)
(click on the image for a larger version)
This is a well-traveled cartoon that simply defines the structure of
a flux rope anchored in the photosphere.
Such a flux rope seems to be the natural organizational state for a
magnetized plasma in space (what other kind is there?).
The rope represents the current flowing through the plasma, driven by some
external EMF or stress, but that is not the whole picture.
In ideal MHD, for example, there is no electrical potential and so all
currents must be locally neutralized.
The cartoon shown here makes the flux rope the fundamental entity of a
CME (flare eruption), and uses the injection of poloidal flux as the
engine of the eruption.
There has been criticism of this model on the grounds that poloidal
flux (a.k.a. vertical current through the photosphere, leading to
the MHD no-no of parallel current) should not vary as rapidly as
required for the eruption.
But never mind.
The resulting dynamics works well enough, so maybe the trivial
question regarding the nature of the initial driving mechanism isn't
so important.
The physical truthiness implied by the continuity of the electric current
is a plus for this cartoon; the Archive contains
others that don't
recognize the need for this.
This cartoon has been an influential one, and it has the very strong
merit that it does not describe CSHKP yet again!
This is a well-traveled cartoon that simply defines the structure of a flux rope anchored in the photosphere. Such a flux rope seems to be the natural organizational state for a magnetized plasma in space (what other kind is there?). The rope represents the current flowing through the plasma, driven by some external EMF or stress, but that is not the whole picture. In ideal MHD, for example, there is no electrical potential and so all currents must be locally neutralized. The cartoon shown here makes the flux rope the fundamental entity of a CME (flare eruption), and uses the injection of poloidal flux as the engine of the eruption. There has been criticism of this model on the grounds that poloidal flux (a.k.a. vertical current through the photosphere, leading to the MHD no-no of parallel current) should not vary as rapidly as required for the eruption. But never mind. The resulting dynamics works well enough, so maybe the trivial question regarding the nature of the initial driving mechanism isn't so important.
The physical truthiness implied by the continuity of the electric current is a plus for this cartoon; the Archive contains others that don't recognize the need for this. This cartoon has been an influential one, and it has the very strong merit that it does not describe CSHKP yet again!