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Title: Recent progress on the development and analysis of the ITPA global H-mode confinement database

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; « less
Publication Date:
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES)
OSTI Identifier:
1170893
Resource Type:
Journal Article
Resource Relation:
Journal Name: Nuclear Fusion; Journal Volume: 47; Journal Issue: 3
Country of Publication:
United States
Language:
English

Citation Formats

D.C,McDonald, J.G,Cordey, K,Thomsen, O.J.W.F,Kardaun, J.A,Snipes, M,Greenwald, L,Sugiyama, F,Ryter, A,Kus, J,Stober, J.C,DeBoo, C.C,Petty, G,Bracco, M,Romanelli, Z,Cui, Y,Liu, Y,Miura, K,Shinohara, K,Tsuzuki, Y,Kamada, T,Takizuka, H,Urano, M,Valovic, R,Akers, C,Brickley, A,Sykes, M.J,Walsh, S.M,Kaye, C,Bush, D,Hogewei, Y.R,Martin, A,Cote, G,Pacher, J,Ongena, F,Imbeaux, G.T,Hoang, S,Lebedev, A,Chudnovskiy, and V,Leonov. Recent progress on the development and analysis of the ITPA global H-mode confinement database. United States: N. p., 2007. Web. doi:10.1088/0029-5515/47/3/001.
D.C,McDonald, J.G,Cordey, K,Thomsen, O.J.W.F,Kardaun, J.A,Snipes, M,Greenwald, L,Sugiyama, F,Ryter, A,Kus, J,Stober, J.C,DeBoo, C.C,Petty, G,Bracco, M,Romanelli, Z,Cui, Y,Liu, Y,Miura, K,Shinohara, K,Tsuzuki, Y,Kamada, T,Takizuka, H,Urano, M,Valovic, R,Akers, C,Brickley, A,Sykes, M.J,Walsh, S.M,Kaye, C,Bush, D,Hogewei, Y.R,Martin, A,Cote, G,Pacher, J,Ongena, F,Imbeaux, G.T,Hoang, S,Lebedev, A,Chudnovskiy, & V,Leonov. Recent progress on the development and analysis of the ITPA global H-mode confinement database. United States. doi:10.1088/0029-5515/47/3/001.
D.C,McDonald, J.G,Cordey, K,Thomsen, O.J.W.F,Kardaun, J.A,Snipes, M,Greenwald, L,Sugiyama, F,Ryter, A,Kus, J,Stober, J.C,DeBoo, C.C,Petty, G,Bracco, M,Romanelli, Z,Cui, Y,Liu, Y,Miura, K,Shinohara, K,Tsuzuki, Y,Kamada, T,Takizuka, H,Urano, M,Valovic, R,Akers, C,Brickley, A,Sykes, M.J,Walsh, S.M,Kaye, C,Bush, D,Hogewei, Y.R,Martin, A,Cote, G,Pacher, J,Ongena, F,Imbeaux, G.T,Hoang, S,Lebedev, A,Chudnovskiy, and V,Leonov. Thu . "Recent progress on the development and analysis of the ITPA global H-mode confinement database". United States. doi:10.1088/0029-5515/47/3/001.
@article{osti_1170893,
title = {Recent progress on the development and analysis of the ITPA global H-mode confinement database},
author = {D.C,McDonald and J.G,Cordey and K,Thomsen and O.J.W.F,Kardaun and J.A,Snipes and M,Greenwald and L,Sugiyama and F,Ryter and A,Kus and J,Stober and J.C,DeBoo and C.C,Petty and G,Bracco and M,Romanelli and Z,Cui and Y,Liu and Y,Miura and K,Shinohara and K,Tsuzuki and Y,Kamada and T,Takizuka and H,Urano and M,Valovic and R,Akers and C,Brickley and A,Sykes and M.J,Walsh and S.M,Kaye and C,Bush and D,Hogewei and Y.R,Martin and A,Cote and G,Pacher and J,Ongena and F,Imbeaux and G.T,Hoang and S,Lebedev and A,Chudnovskiy and V,Leonov},
abstractNote = {},
doi = {10.1088/0029-5515/47/3/001},
journal = {Nuclear Fusion},
number = 3,
volume = 47,
place = {United States},
year = {Thu Mar 01 00:00:00 EST 2007},
month = {Thu Mar 01 00:00:00 EST 2007}
}
  • Results are presented from analysis of the database for {open_quotes}quiescent{close_quotes} (i.e., without ELM) H mode of confinement. It is shown that the only parameter (aside from a constant factor) in terms of which the scaling law must be modified for the H mode in comparison with that of the L mode is the dependence on the plasma elongation k = b/a. As a result of the analysis a power-law scaling is found for the quiescent H mode which can be written in the simple form {tau}{sub E}{sup HE} = 1.5 x {tau}{sub E}{sup IT-89-L} x k{sup 0.63}, where {tau}{sub E}{supmore » IT-89-L} is the ITER-89-L scaling for L mode. This new scaling law describes the experimental data better than previously obtained scaling laws for the H mode and can be recommended for estimating the confinement time in future tokamaks (ITER, DEMO). 7 refs., 11 figs., 3 tabs.« less
  • A multi-device database of disruption characteristics has been developed under the auspices of the International Tokamak Physics Activity magneto hydrodynamics topical group. The purpose of this ITPA Disruption Database (IDDB) is to find the commonalities between the disruption and disruption mitigation characteristics in a wide variety of tokamaks in order to elucidate the physics underlying tokamak disruptions and to extrapolate toward much larger devices, such as ITER and future burning plasma devices. Conversely, in order to previous smaller disruption data collation efforts, the IDDB aims to provide significant context for each shot provided, allowing exploration of a wide array ofmore » relationships between pre-disruption and disruption parameters. Furthermore, the IDDB presently includes contributions from nine tokamaks, including both conventional aspect ratio and spherical tokamaks. An initial parametric analysis of the available data is presented. Our analysis includes current quench rates, halo current fraction and peaking, and the effectiveness of massive impurity injection. The IDDB is publicly available, with instruction for access provided herein.« less
  • Here, recent experiments in DIII-D have led to the discovery of a means of modifying edge turbulence to achieve stationary, high confinement operation without Edge Localized Mode (ELM) instabilities and with no net external torque input. Eliminating the ELM-induced heat bursts and controlling plasma stability at low rotation represent two of the great challenges for fusion energy. By exploiting edge turbulence in a novel manner, we achieved excellent tokamak performance, well above the H 98y2 international tokamak energy confinement scaling (H 98y2=1.25), thus meeting an additional confinement challenge that is usually difficult at low torque. The new regime is triggeredmore » in double null plasmas by ramping the injected torque to zero and then maintaining it there. This lowers ExB rotation shear in the plasma edge, allowing low-k, broadband, electromagnetic turbulence to increase. In the H-mode edge, a narrow transport barrier usually grows until MHD instability (a peeling ballooning mode) leads to the ELM heat burst. However, the increased turbulence reduces the pressure gradient, allowing the development of a broader and thus higher transport barrier. A 60% increase in pedestal pressure and 40% increase in energy confinement result. An increase in the ExB shearing rate inside of the edge pedestal is a key factor in the confinement increase. Strong double-null plasma shaping raises the threshold for the ELM instability, allowing the plasma to reach a transport-limited state near but below the explosive ELM stability boundary. The resulting plasmas have burning-plasma-relevant ╬▓ N=1.6-1.8 and run without the need for extra torque from 3D magnetic fields. To date, stationary conditions have been produced for 2 s or 12 energy confinement times, limited only by external hardware constraints. Stationary operation with improved pedestal conditions is highly significant for future burning plasma devices, since operation without ELMs at low rotation and good confinement is key for fusion energy production.« less