What will happen to the solar corona at red giant phase?

[newtonian]

A spin off from my surviving red giant phase thread.<br /><br />What will happen to the solar corona at red giant phase?<br /><br />We know it is heated by magnetic fields, not solar fusion.<br /><br />How would switching from hydrogen fusion to helium fusion effect the magnetic field dynamos within the sun?<br /><br />Would the fields become weaker, thus cooling the corona?<br /><br />Also, is the future of earth's orbit at red giant phase going to include entry into the solar corona - or will said corona have dissipated by then, or will said corona be within solar surface instead of above it as at present?<br /><br />Do other red giants have coronas?