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arXiv · 1907.00492

First Results from an Event Synchronized -- High Repetition Thomson Scattering System at Wendelstein 7-X

Hannes Damm·Ekkehard Pasch·Andreas Dinklage·Jürgen Baldzuhn·Sergey Bozhenkov·Kai Jakob Brunner·Florian Effenberg·Golo Fuchert·Joachim Geiger·Jeffrey Harris·Jens Knauer·Petra Kornejew·Thierry Kremeyer·Maciej Krychowiak·Jonathan Schilling·Oliver Schmitz·Evan Scott·Victoria Winters·the Wendelstein 7-X Team
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Abstract

The Wendelstein 7-X (W7-X) Thomson scattering (TS) diagnostic was upgraded to transiently achieve kilohertz sampling rates combined with adjustable measuring times. The existing Nd:YAG lasers are employed to repetitively emit "bursts", i.e. multiple laser pulses in a short time interval. Appropriately timing burst in the three available lasers, up to twelve evenly spaced consecutive measurements per burst are possible. The pulse-to-pulse increment within a burst can be tuned from 2 ms to 33.3 ms (500 kHz - 30 Hz). Additionally, an event trigger system was developed to synchronize the burst Thomson scattering measurements to plasma events. Exemplary, a case of fast electron density and temperature evolution after cryogenic H2 pellet injection is presented in order to demonstrate the capabilities of the method.

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Hannes Damm, Ekkehard Pasch, Andreas Dinklage, Jürgen Baldzuhn, Sergey Bozhenkov, Kai Jakob Brunner, Florian Effenberg, Golo Fuchert, Joachim Geiger, Jeffrey Harris, Jens Knauer, Petra Kornejew, Thierry Kremeyer, Maciej Krychowiak, Jonathan Schilling, Oliver Schmitz, Evan Scott, Victoria Winters, the Wendelstein 7-X Team. 2019-06-30. First Results from an Event Synchronized -- High Repetition Thomson Scattering System at Wendelstein 7-X. https://doi.org/10.1088/1748-0221%2F14%2F09%2Fc09037

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