Physics of Plasmas最新文献_第6页

Localization of beam generated whistler wave and turbulence generation in reconnection region of magnetopause 磁层顶重联区域束流产生的啸波定位和湍流生成

Physics of Plasmas Pub Date : 2024-02-01 DOI: 10.1063/5.0169397

Jyoti, Suresh C. Sharma, R. P. Sharma

{"title":"Localization of beam generated whistler wave and turbulence generation in reconnection region of magnetopause","authors":"Jyoti, Suresh C. Sharma, R. P. Sharma","doi":"10.1063/5.0169397","DOIUrl":"https://doi.org/10.1063/5.0169397","url":null,"abstract":"Whistler waves have been studied for many years in relation to turbulence and particle heating, and observations show that they are crucial to magnetic reconnection. Recent research has revealed a close relationship between magnetic reconnection and turbulence. The current work investigates the whistler turbulence caused by the energetic electron beam in the magnetic reconnection sites of magnetopause and also due to dynamic evolution of magnetic islands. For this, we develop a model based upon the two-fluid approximation to study whistler dynamics, propagating in the medium with the pre-existing chain of magnetic islands and under the influence of background density perturbation originating from ponderomotive nonlinearity of wave. Dynamics of nonlinear whistler have been solved with pseudo-spectral approach and a finite difference method with a modified predictor–corrector method and a Runge Kutta method for the semianalytical model. In the current research, we study how the nonlinear whistler wave contributes to the significant space phenomenon, i.e., turbulence, localization, and magnetic reconnection. We have also investigated the formation of a current sheet in a magnetopause region of the order of few-electron inertial length. We analyzed the power spectrum at the magnetopause when the system reached a quasi-steady condition. Our new approach to study whistler turbulence by an energetic electron beam at the magnetic reconnection sites has extensive applications to space plasmas, shedding a new light on the study of magnetic reconnection in nature.","PeriodicalId":510396,"journal":{"name":"Physics of Plasmas","volume":"189 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139821512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Experimental evidence of enhanced radial transport in small ELM regimes at DIII-D DIII-D 小型 ELM 系统径向输运增强的实验证据

Physics of Plasmas Pub Date : 2024-02-01 DOI: 10.1063/5.0181309

R. Perillo, J. Boedo, C. Lasnier, A. McLean, I. Bykov, C. Marini, D. Rudakov, J. Watkins

{"title":"Experimental evidence of enhanced radial transport in small ELM regimes at DIII-D","authors":"R. Perillo, J. Boedo, C. Lasnier, A. McLean, I. Bykov, C. Marini, D. Rudakov, J. Watkins","doi":"10.1063/5.0181309","DOIUrl":"https://doi.org/10.1063/5.0181309","url":null,"abstract":"Small/type-II edge-localized-modes (ELMs), carrying 1% of the plasma stored energy, are found to deposit only 45 ± 5% of the ELM power near the strike point, and the remaining 55 ± 5% to the far scrape-off-layer (SOL). Small ELMs spread their power over a larger area compared to type-I ELMs, where such a ratio is about 60% and 40% for near- and far-SOL regions, respectively. The larger spread is reflected in the heat flux width (λq) in the SOL for the intra-small ELMs profile of 6.0 mm, almost a factor 2 larger than that of type-I ELMs of 3.15 mm, for similar plasma conditions and magnetic configuration. At the ELM peak, the small ELMs λq is found to be up to 4 times larger than for the type-I ELMs, going from 2 to 7.9 mm, indicating enhanced radial transport in the neon-seeded small ELM scenario. Inter-ELM λqs have been also calculated at the secondary outer divertor in quasi-double-null (QDN) discharges. It is found that, on average, λq is 2.2 times larger in the high-separatrix-density small ELM regime, compared to a reference type-I ELM one. These findings are supported by small ELMs radial velocity profiles, measured at the outer midplane with a fast reciprocating probe, showing a decay length (λvr) in the SOL of 12.8 cm, which is 3.3 times larger than that for the type-I ELMs of 3.9 cm. This analysis shows that small ELMs, although attractive for future machines due to low peak heat flux and large λq, might be of concern for the larger flux to the outer wall.","PeriodicalId":510396,"journal":{"name":"Physics of Plasmas","volume":"5 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139873780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Impact of divertor neutral pressure on confinement degradation of advanced tokamak scenarios at ASDEX Upgrade 分流器中性压力对 ASDEX 升级版先进托卡马克方案约束退化的影响

Physics of Plasmas Pub Date : 2024-02-01 DOI: 10.1063/5.0184405

D. Silvagni, M. Dunne, T. Luda, A. Bock, A. Burckhart, R. Fischer, M. Griener, R. M. McDermott, U. Plank, T. Pütterich, M. Reisner, J. Stober, B. Tal, G. Tardini, H. Zohm

{"title":"Impact of divertor neutral pressure on confinement degradation of advanced tokamak scenarios at ASDEX Upgrade","authors":"D. Silvagni, M. Dunne, T. Luda, A. Bock, A. Burckhart, R. Fischer, M. Griener, R. M. McDermott, U. Plank, T. Pütterich, M. Reisner, J. Stober, B. Tal, G. Tardini, H. Zohm","doi":"10.1063/5.0184405","DOIUrl":"https://doi.org/10.1063/5.0184405","url":null,"abstract":"Over previous campaigns, an intense experimental program on advanced tokamak (AT) scenarios, has been carried out at the ASDEX Upgrade tokamak with full-tungsten wall. These discharges have been executed shortly after the boronization of the first wall to reduce the density and the impurity influx. The confinement level of such AT discharges was found to vary considerably, even when discharges with similar, if not identical, engineering parameters were carried out. This work investigates the causes of such confinement variations. Among all plasma quantities analyzed, confinement quality of AT scenarios correlates best with divertor neutral pressure, highlighting the key role of edge and scrape-off layer physics in determining global plasma confinement. In particular, it is found that the main cause of confinement degradation is the reduction of pedestal stability, which is in turn caused by the outward shift of the maximum density gradient position typically observed when the divertor neutral pressure increases. Owing to the low density of AT discharges under analysis, the movement of the maximum density gradient position can be caused entirely by changes in deuterium outgassing from the wall, which is strongly influenced by the boron layer deposited on the plasma-facing components and by the deuterium wall inventory. Finally, the predictive capability of confinement quality with the integrated model IMEP [Luda et al., Nucl. Fusion 60, 036023 (2020)] is tested on these discharges and shows promising results.","PeriodicalId":510396,"journal":{"name":"Physics of Plasmas","volume":"41 24","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139880751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Localization of beam generated whistler wave and turbulence generation in reconnection region of magnetopause 磁层顶重联区域束流产生的啸波定位和湍流生成

Physics of Plasmas Pub Date : 2024-02-01 DOI: 10.1063/5.0169397

Jyoti, Suresh C. Sharma, R. P. Sharma

{"title":"Localization of beam generated whistler wave and turbulence generation in reconnection region of magnetopause","authors":"Jyoti, Suresh C. Sharma, R. P. Sharma","doi":"10.1063/5.0169397","DOIUrl":"https://doi.org/10.1063/5.0169397","url":null,"abstract":"Whistler waves have been studied for many years in relation to turbulence and particle heating, and observations show that they are crucial to magnetic reconnection. Recent research has revealed a close relationship between magnetic reconnection and turbulence. The current work investigates the whistler turbulence caused by the energetic electron beam in the magnetic reconnection sites of magnetopause and also due to dynamic evolution of magnetic islands. For this, we develop a model based upon the two-fluid approximation to study whistler dynamics, propagating in the medium with the pre-existing chain of magnetic islands and under the influence of background density perturbation originating from ponderomotive nonlinearity of wave. Dynamics of nonlinear whistler have been solved with pseudo-spectral approach and a finite difference method with a modified predictor–corrector method and a Runge Kutta method for the semianalytical model. In the current research, we study how the nonlinear whistler wave contributes to the significant space phenomenon, i.e., turbulence, localization, and magnetic reconnection. We have also investigated the formation of a current sheet in a magnetopause region of the order of few-electron inertial length. We analyzed the power spectrum at the magnetopause when the system reached a quasi-steady condition. Our new approach to study whistler turbulence by an energetic electron beam at the magnetic reconnection sites has extensive applications to space plasmas, shedding a new light on the study of magnetic reconnection in nature.","PeriodicalId":510396,"journal":{"name":"Physics of Plasmas","volume":"19 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139881242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Experimental evidence of enhanced radial transport in small ELM regimes at DIII-D DIII-D 小型 ELM 系统径向输运增强的实验证据

Physics of Plasmas Pub Date : 2024-02-01 DOI: 10.1063/5.0181309

R. Perillo, J. Boedo, C. Lasnier, A. McLean, I. Bykov, C. Marini, D. Rudakov, J. Watkins

{"title":"Experimental evidence of enhanced radial transport in small ELM regimes at DIII-D","authors":"R. Perillo, J. Boedo, C. Lasnier, A. McLean, I. Bykov, C. Marini, D. Rudakov, J. Watkins","doi":"10.1063/5.0181309","DOIUrl":"https://doi.org/10.1063/5.0181309","url":null,"abstract":"Small/type-II edge-localized-modes (ELMs), carrying 1% of the plasma stored energy, are found to deposit only 45 ± 5% of the ELM power near the strike point, and the remaining 55 ± 5% to the far scrape-off-layer (SOL). Small ELMs spread their power over a larger area compared to type-I ELMs, where such a ratio is about 60% and 40% for near- and far-SOL regions, respectively. The larger spread is reflected in the heat flux width (λq) in the SOL for the intra-small ELMs profile of 6.0 mm, almost a factor 2 larger than that of type-I ELMs of 3.15 mm, for similar plasma conditions and magnetic configuration. At the ELM peak, the small ELMs λq is found to be up to 4 times larger than for the type-I ELMs, going from 2 to 7.9 mm, indicating enhanced radial transport in the neon-seeded small ELM scenario. Inter-ELM λqs have been also calculated at the secondary outer divertor in quasi-double-null (QDN) discharges. It is found that, on average, λq is 2.2 times larger in the high-separatrix-density small ELM regime, compared to a reference type-I ELM one. These findings are supported by small ELMs radial velocity profiles, measured at the outer midplane with a fast reciprocating probe, showing a decay length (λvr) in the SOL of 12.8 cm, which is 3.3 times larger than that for the type-I ELMs of 3.9 cm. This analysis shows that small ELMs, although attractive for future machines due to low peak heat flux and large λq, might be of concern for the larger flux to the outer wall.","PeriodicalId":510396,"journal":{"name":"Physics of Plasmas","volume":"56 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139814001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0