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Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser
Published on: June 28, 2018
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Spectrally resolved polarization angle across the motional Stark effect spectrum
B S Victor1, S L Allen1, C T Holcomb1
1Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
The Review of Scientific Instruments
|July 10, 2021
Summary
A novel diagnostic technique enhances plasma measurement by integrating a spectrometer and camera with the motional Stark effect (MSE) system. This advancement allows for detailed spectral analysis of plasma polarization, improving diagnostic accuracy.
Area of Science:
- Physics
- Plasma Physics
- Spectroscopy
Background:
- The motional Stark effect (MSE) system is crucial for diagnosing plasma properties in fusion devices.
- Accurate measurement of plasma polarization is essential for understanding plasma behavior and confinement.
Purpose of the Study:
- To develop and implement a new diagnostic technique that improves spectral and polarization measurements in plasma.
- To integrate a spectrometer and image-intensified camera into the existing MSE system.
Main Methods:
- Coupling a spectrometer and an image-intensified camera to a traditional motional Stark effect (MSE) system.
- Synchronizing the camera with photo-elastic modulators to spectrally resolve Stokes parameters across the Stark multiplet.
- Analyzing polarization-dependent phase shifts impacting the spectropolarimeter measurements.
Main Results:
- The new diagnostic system successfully spectrally resolves Stokes parameters across the Stark multiplet.
- A polarization-dependent phase shift was identified, likely originating from a plasma-facing mirror.
- The spectropolarimeter measured a significant variation in polarization angle (approximately 8°) across the MSE spectrum.
Conclusions:
- The integrated diagnostic technique offers enhanced capabilities for plasma characterization.
- Understanding polarization variations is critical for refining MSE-based plasma diagnostics.
- Further investigation into the source of polarization-dependent phase shifts is warranted to optimize diagnostic performance.
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