I'm reading some literature on mass loss in the RGB/AGB branches and so far I'm getting a lot of information regarding mass loss via dusty-winds/pulsations but almost no explanation of mass loss by 'chromosphere activity'. I asked my mentor about it and he couldn't come up with anything so I'm turning to whomever might be able to throw a few references or explanations my way.
I guess what is meant is mass loss powered by non-radiative heating occurring above the photosphere. i.e The outer atmosphere is heated by magnetic Alfven waves and causes a wind to stream away from the star. The same magnetic field is responsible for heating a chromosphere - a hotter layer above the photosphere.
Here is a paper by Schroder and Cuntz (2005), though not really at an introductory level.
An update: Recent theoretical modelling claims to have reproduced some of the mass loss and chromospheric properties of the K5 giant Aldeberan, through the dissipation of Alfven waves in the chromosphere.
Airapetian et al. (2014) - http://arxiv.org/pdf/1409.3833v1.pdf