Radio Frequency(RF) Diagnostic for Energetic Particle and Wave-particle Interaction Study in KSTAR
- Title
- Radio Frequency(RF) Diagnostic for Energetic Particle and Wave-particle Interaction Study in KSTAR
- Authors
- YUN, GUNSU
- Date Issued
- 2023-08-25
- Publisher
- 한국물리학회, 한국진공학회, Korea Accelerator and Plasma Research Association
- Abstract
- Energetic particles are the essential component in the transport processes and stability of fusion plasmas [1], in particular of the burning plasmas that produce high-energy alpha particles. As a potential energetic particle diagnostic, the radio frequency (RF) spectroscopy is suggested as an effective method for its non-invasiveness and small footprint [2–5]. In KSTAR, we have developed a fast RF diagnostic system with the temporal and spectral resolutions of Δf_res~0.5 MHz and Δt_res~1 μs for the study of wave-particle interactions. The RF system implemented two different types of measurement. One is the direct measurement by spiral-shaped antennas (f=0.1–0.88 GHz) located in front of the KSTAR H-port aperture [4, 6], and the other is an indirect measurement of whistler-frequency range (~GHz) waves embedded in the electron cyclotron emissions which are measured by mm-wave mixer antennas [7]. One of the common wave phenomena that drew our attention is the edge deuterium ion cyclotron harmonic emissions (d-ICEs) and their dynamic changes in KSTAR H-mode discharges. Edge d-ICEs are routinely observed in both KSTAR ELMy and ELM-suppressed H-mode discharges. During the inter-ELM-crash periods, the d-ICE harmonics frequency range and intensity drastically change. Fast-ion Dα (FIDA) [8] measurement shows that the edge beam-ion fraction increases with the appearance of the ELM filament [9]. Full-orbit simulations with the Lorentz-orbit (LORBIT) code [10] suggest that the fast ion orbits move outward during the period of edge d-ICE enhancement. These observations are consistent with the previous study on the beam-driven ICE using 1D3V particle-in-cell simulations [11]. Our study shows that RF diagnostic can be a quantitative indicator of the presence of fast ions at the outer edge region.
This work was supported by the R&D programs of “KSTAR Experimental Collaboration and Fusion Plasma Research” (KFE Grant Code: EN2301-14) and “ITER Burning Plasma Research and Development of ITER Plasma Exploitation Plan” (KFE Grant Code: IN2304-9) through the Korea Institute of Fusion Energy (KFE) funded by the Government funds.
References
[1] D. Moseev et al., Rev. Mod. Plasma Phys., 2:7, 1–68 (2018)
[2] G.H. DeGrandchamp et al., Rev. Sci. Instrum., 92, 033543 (2021)
[3] R. Ochoukov et al., Rev. Sci. Instrum., 86, 115112 (2015)
[4] M.H. Kim et al., Nucl. Fusion., 58, 096034 (2018)
[5] D. Moseev et al., Rev. Sci. Instrum., 92, 033546 (2021)
[6] S.G. Thatipamula et al., Plasma Phys. Control. Fusion, 58, 065003 (2016)
[7] M.H. Kim et al., Nucl. Fusion., 60, 120621 (2020)
[8] J.W. Yoo et al., Rev. Sci. Instrum., 92, 043504 (2021)
[9] M.H. Kim et al., 29th Meetings of ITPA Topical Group on Energetic Particle Physics, May 23rd–26th, Oak Ridge National Lab, TN, USA (2023)
[10] M. Isobe et al., J. Plasma Fusion Res., 8, 330 (2009)
[11] B. Chapman et al., Nucl. Fusion, 59, 106021 (2019)
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/119832
- Article Type
- Conference
- Citation
- The 2nd International Fusion and Plasma Conference, 2023-08-25
- Files in This Item:
- There are no files associated with this item.
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.