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Jian X, Chen J, Ding S, Garofalo A, Gong X, Holland C, Huang J, Chan VS, Qin X, Yu G, Ma RR, Du X, Hong R, Staebler G, Wang H, Yan Z, Bass E, Brower D, Ding W, Orlov D. Experimental Validation of a Kinetic Ballooning Mode in High-Performance High-Bootstrap Current Fraction Fusion Plasmas. Phys Rev Lett 2023; 131:145101. [PMID: 37862644 DOI: 10.1103/physrevlett.131.145101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 07/09/2023] [Accepted: 08/21/2023] [Indexed: 10/22/2023]
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.
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Affiliation(s)
- X Jian
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, China
- University of California, San Diego, La Jolla, California 92093-0417, USA
| | - J Chen
- University of California Los Angeles, Los Angeles, California 90095, USA
| | - S Ding
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
| | - A Garofalo
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
| | - X Gong
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - C Holland
- University of California, San Diego, La Jolla, California 92093-0417, USA
| | - J Huang
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - V S Chan
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
| | - X Qin
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - G Yu
- University of California at Davis, Davis, California 95616, USA
| | - R R Ma
- Southwestern Institute of Physics, P.O. Box 432 Chengdu 610041, China
| | - X Du
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
| | - R Hong
- University of California Los Angeles, Los Angeles, California 90095, USA
| | - G Staebler
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
| | - H Wang
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
| | - Z Yan
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - E Bass
- University of California, San Diego, La Jolla, California 92093-0417, USA
| | - D Brower
- University of California Los Angeles, Los Angeles, California 90095, USA
| | - W Ding
- University of California Los Angeles, Los Angeles, California 90095, USA
| | - D Orlov
- University of California, San Diego, La Jolla, California 92093-0417, USA
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Ma RR, Xiong T, Bao Y. The Russia-Saudi Arabia oil price war during the COVID-19 pandemic. Energy Econ 2021; 102:105517. [PMID: 34898736 PMCID: PMC8652835 DOI: 10.1016/j.eneco.2021.105517] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 08/06/2021] [Accepted: 08/07/2021] [Indexed: 06/14/2023]
Abstract
The COVID-19 pandemic damaged crude oil markets and amplified the consequences of uncertainty stemming from the Russia-Saudi Arabia oil price war in March-April of 2020. We investigate the impacts of the oil price war on global crude oil markets. By doing so, we use the daily futures and spot prices in three major crude oil markets - West Texas Intermediate, European Brent, and Oman - to perform a systematic analysis of the impacts of the oil price war on them. The event study method, a well-established analytical tool to measure the impacts of a given event on markets, is used in this study. The results indicate that information leakage plays an important role in the impacts of the price war. The outbreak of and truce following the price war have asymmetrical impacts on the markets; negative impacts generated by information leakage during the outbreak are generally more durable than the positive ones it generated during the truce. Furthermore, the magnitude of the impacts on futures markets is negatively correlated with the time-to-maturity of futures. Finally, negative crude oil prices affect West Texas Intermediate crude oil markets the most. Our findings generally show that market participants could perceive and assimilate market changes and adjust their expectations, which restrained the impacts that should have occurred within the oil price war.
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Affiliation(s)
- Richie Ruchuan Ma
- Department of Agricultural & Consumer Economics, University of Illinois at Urbana-Champaign, 438 Mumford Hall, 1301 W. Gregory Dr., Urbana, IL 61801, United States
| | - Tao Xiong
- Department of Agricultural Economics and Management, College of Economics & Management, Huazhong Agricultural University, No.1 Shizishan St., Hongshan Dist., Wuhan 430070, Hubei Province, PR China
| | - Yukun Bao
- Department of Business Administration, School of Management, Huazhong University of Science and Technology, 1307 Luoyu Rd., Hongshan Dist., Wuhan 430074, Hubei Province, PR China
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Abstract
This work contributes to the development of a common framework for the discussion and analysis of dexterous manipulation across the human and robotic domains. An overview of previous work is first provided along with an analysis of the tradeoffs between arm and hand dexterity. A hand-centric and motion-centric manipulation classification is then presented and applied in four different ways. It is first discussed how the taxonomy can be used to identify a manipulation strategy. Then, applications for robot hand analysis and engineering design are explained. Finally, the classification is applied to three activities of daily living (ADLs) to distinguish the patterns of dexterous manipulation involved in each task. The same analysis method could be used to predict problem ADLs for various impairments or to produce a representative benchmark set of ADL tasks. Overall, the classification scheme proposed creates a descriptive framework that can be used to effectively describe hand movements during manipulation in a variety of contexts and might be combined with existing object centric or other taxonomies to provide a complete description of a specific manipulation task.
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