Heating the chromosphere: what is the problem and possible solutions.
Heating in the solar atmosphere
T. D. Arber
University of Warwick
C. S. Brady - University of Wrawick
The chromospheric a Poynting flux of about 2x10^7 erg/s/cm^2 to maintain the average atmosphere against radiative and conductive losses. This is orders of magnitude more than the requirements for the corona. Possible heating mechanisms have been proposed for over fifty years but this is still an unsolved problem. Partly this is due to the complexity of chromospheric observations but mostly it is the intrinsic complexity of the chromosphere itself - low to high beta, compressible, partially ionised, optically thick to thin and stratified. Despite this complexity there is growing evidence that theories proposed in the 1908’s (Hollweg et al.) on shock heating may be the dominant heating mechanism for the mid and app chromosphere.
Following a review of the heating problem and possible solutions we go on to show that driving Alfven and kink waves into an expanding flux tube it is possible to reproduce a heating profile broadly consistent with the middle to upper chromosphere. The heating mechanism is through ponderomotive coupling of Alfven waves to shock and it is the shocks which dissipate and heat. These same shocks also produce jets similar to spicules (Type-I) which have the correct rise speed and transverse oscillations.


09:00 - 10:30
EX - C3 (150)