Magnetic reconnection lies at the heart of much stellar phenomena in the cool half of the H-R diagram, and X-ray studies of stellar coronae have revealed the intricate interplay of plasma and magnetic fields, ultimately produced as the result of a dynamo process. The breakthrough of Chandra and XMM-Newtons high resolution spectrometers for these stars lay in revealing the wealth of diagnostic information, used to demonstrate the structuring and energetics of hot plasma, and the extent to which magnetic fields shape and influence stellar surroundings. In this talk I will describe how high resolution, high throughput spectra with the XRS continue the challenge of linking a well-studied star like our Sun with representative stellar samples to probe dynamos in the stellar extremes of thick/thin outer convection zones, and time-varying influences of magnetic fields.

Session 4: Physics of New Worlds Chair: Martin Laming