Hugh, The saturation level of loop tangling determines the average transverse field strength. Also, I think the loop would presumably distribute its stored energy more or less evenly along its length. That means that the transverse field strength at the base of the loop is affected by the amount of loop tangling. The Poynting flux is proportional to V B_trans B_z, where V is the fluid velocity, B_z the vertical field, and B_trans the horizontal component of the field. The convection zone supplies V and adds some new B_trans, but the boundary conditions on the existing coronal field give you some B_trans as well. Mitch
On Fri, Mar 6, 2009 at 4:53 PM, Hugh Hudson hhudson@ssl.berkeley.edu wrote:
Surely the power input is dictated by the Poynting flux at the base, and so any saturation level of loop tangling has nothing to do with it? Otherwise one would have to be extracting energy out of the corona itself, rather than the convection zone. Hugh