Bradshaw, Stephen J.Raymond, John2013-03-262014-03-272013Bradshaw, Stephen J. and Raymond, John. "Collisional and Radiative Processes in Optically Thin Plasmas." <i>Space Science Reviews,</i> (2013) Springer Science+Business Media: http://dx.doi.org/10.1007/s11214-013-9970-0.https://hdl.handle.net/1911/70838Most of our knowledge of the physical processes in distant plasmas is obtained through measurement of the radiation they produce. Here we provide an overview of the main collisional and radiative processes and examples of diagnostics relevant to the microphysical processes in the plasma. Many analyses assume a time-steady plasma with ion populations in equilibrium with the local temperature and Maxwellian distributions of particle velocities, but these assumptions are easily violated in many cases. We consider these departures from equilibrium and possible diagnostics in detail.engArticle is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.Journal articlemicrophysical processeshttp://dx.doi.org/10.1007/s11214-013-9970-0