Abstract
We report the observation of a set of coherent high frequency electromagnetic fluctuations that leads to a turbulence induced self-regulating phenomenon in the DIII-D high bootstrap current fraction plasma. The fluctuations have frequency of 130-220 kHz, the poloidal wavelength and phase velocity are 16-30 m-1 and ∼30 km/s, respectively, in the outboard midplane with the estimated toroidal mode number n∼5-9. The fluctuations are located in the internal transport barrier (ITB) region at large radius and are experimentally validated to be kinetic ballooning modes (KBM). Quasilinear estimation predicts the KBM to be able to drive experimental particle flux and non-negligible thermal flux, suggesting its significant role in regulating the ITB saturation.
| Original language | English |
|---|---|
| Article number | 145101 |
| Journal | Physical Review Letters |
| Volume | 131 |
| Issue number | 14 |
| DOIs | |
| State | Published - Oct 6 2023 |
| Externally published | Yes |
Funding
Discussions with Y. Zou in SWIP, T. Rhodes in UCLA, G. McKee in UW Madison, P. J. Sun in ASIPP, Z. Li and J. Candy in General Atomics are appreciated. We also appreciate X. R. Zhang in DLUT for proof reading, Bart Van Compernollein GA for his support and the anonymous referees for many helpful suggestions. This work was supported by the U.S. Department of Energy under Awards No. DE-SC0018287, No. DE-SC0017992, No. DE-FG02-95ER54309, No. DE-SC0019004, No. DE-FG02-08ER54999, No. DE-FG02-99ER54531, No. DE-SC0019352, and No. DE-FC02-04ER54698. This work is also supported by, Anhui Provincial Key R&D Programmes No. 202104b11020003. This research used resources of the National Energy Research Scientific Computing Center (NERSC); a U.S. Department of Energy Office of Science User Facility operated under Contract No. DEAC02-05CH11231 using NERSC Grant No. ERCAP0020598. This Letter was prepared as an account of work sponsored by an agency of the United States Government. Neither the U.S. Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the U.S. Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the U.S. Government or any agency thereof.
| Funders | Funder number |
|---|---|
| Anhui Provincial Key R&D Programmes | 202104b11020003 |
| U.S. Department of Energy | DE-SC0019352, DE-FG02-08ER54999, DE-SC0018287, DE-FC02-04ER54698, DE-FG02-99ER54531, DE-SC0017992, DE-SC0019004, DE-FG02-95ER54309 |
| Office of Science | DEAC02-05CH11231, ERCAP0020598 |
