NSTX

http://www.pppl.gov/nstx-u
http://www.pppl.gov/nstx

The real time multi point Thomson scattering diag-
nostic at NSTX-U

As a key diagnostic at NSTX-U, the multi point Thomson scattering (MPTS) diagnostic simultaneously measures the electron density (ne) and electron temperature (Te) profiles of a plasma discharge. Therefore, this powerful diagnostic can directly access the electron pressure of the plasma. Currently, only post-discharge evaluation of the data is available, however, since the plasma pressure is one important drive for instabilities, real time measurements of this quantities would be beneficial for plasma control. In a first step, ten MPTS channels were equipped with real time electronics, which improve the data acquisition rate by five orders of magnitude. The commissioning of the system is ongoing and first benchmarks of the real time evaluation routines against the standard, post-discharge evaluation show promising results: The Te as well as ne profiles of both types of analyses (rt and post-discharge) agree within their uncertainties.