How is the energy relased in the corona? Or, how
to cut and paste a rubber band.
We have learnt that the convective motions below the
photosphere provide the energy needed to heat the corona.
We also know that the
magnetic field rooted in the convection zone
can carry some of
this energy into the corona. But how is it released?
The different time scale for the motions in the convection cells provide
two different types of energy release.
-
If the timescale for the convective motions are fast compared
to the time it takes for information to travel along the magnetic field
line, then the magnetic field lines are shaken with waves,
just like a guitar string.
This is know as
AC (Alternating Current) heating.
-
If the time scale for the convective motion is longer than the
travel time for information along the field line,
then the field line is moved more like
a rigid body (such as a plank of wood).
This is known as DC (Direct Current) heating.
