[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"doc-seo-153991-105":3,"detail-sidebar-cat-0-en-105":81,"doc-detail-153991-en":130},{"code":4,"msg":5,"data":6},0,"ok",{"site_id":7,"language":8,"slug":9,"title":10,"keywords":11,"description":12,"schema_data":13,"social_meta":74,"head_meta":76,"extra_data":78,"updated_unix":80},105,"en","alpha-physics-and-measurement-requirements-for-iter-preprint","Alpha-Physics and Measurement Requirements for ITER - Preprint","","This paper reviews alpha particle physics issues in ITER and their implications for alpha particle measurements. It compares alpha heating in ITER with NBI and ICRH heating systems used in present tokamaks, highlighting differences in expected alpha density, beta, and fast-ion physics. The discussion is organized into three areas: single-particle alpha effects, collective alpha effects, and RF interactions with alpha particles, addressing diagnostic needs for predicting heating and managing loss.",{"@graph":14,"@context":73},[15,34,56],{"@type":16,"itemListElement":17},"BreadcrumbList",[18,23,27,31],{"item":19,"name":20,"@type":21,"position":22},"https://docshare.wps.com","Home","ListItem",1,{"item":24,"name":25,"@type":21,"position":26},"https://docshare.wps.com/document/","Document",2,{"item":28,"name":29,"@type":21,"position":30},"https://docshare.wps.com/document/research-report/","Research & 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ITER harder to predict and control than NBI/ICRH heating?","Question",{"text":63,"@type":64},"Alpha particle creation depends strongly on plasma conditions, and heating and loss also depend on alpha transport during their long thermalization time (~1 s) with possible MHD activity and nonaxisymmetries.","Answer",{"name":66,"@type":61,"acceptedAnswer":67},"How does ITER alpha heating compare with fast ion heating in present tokamaks?",{"text":68,"@type":64},"ITER alpha heating power density is expected to be lower, with alpha particle density typically about an order of magnitude lower than NBI fast-ion density, and an ITER alpha beta smaller than most auxiliary-heated tokamak values.",{"name":70,"@type":61,"acceptedAnswer":71},"What are the main physics areas used to discuss alpha particle issues in ITER?",{"text":72,"@type":64},"The paper discusses three areas: single-particle alpha effects, collective alpha effects, and RF interactions with alpha particles.","https://schema.org",{"og:url":32,"og:type":75,"og:title":10,"og:site_name":45,"og:description":12},"article",{"robots":77,"canonical":32},"index,follow",{"doc_id":79,"site_id":7},153991,1787884704,{"code":4,"msg":82,"data":83},"success",[84,88,92,96,100,105,110,114,119,122,126],{"id":22,"doc_module":4,"doc_module_name":25,"category_name":85,"show_sort_weight":86,"slug":87},"Story & Novel",90,"story-novel",{"id":26,"doc_module":4,"doc_module_name":25,"category_name":89,"show_sort_weight":90,"slug":91},"Literature",80,"literature",{"id":33,"doc_module":4,"doc_module_name":25,"category_name":93,"show_sort_weight":94,"slug":95},"Exam",70,"exam",{"id":55,"doc_module":4,"doc_module_name":25,"category_name":97,"show_sort_weight":98,"slug":99},"Comic",60,"comic",{"id":101,"doc_module":4,"doc_module_name":25,"category_name":102,"show_sort_weight":103,"slug":104},6,"Technology",50,"technology",{"id":106,"doc_module":4,"doc_module_name":25,"category_name":107,"show_sort_weight":108,"slug":109},7,"Healthcare",40,"healthcare",{"id":111,"doc_module":4,"doc_module_name":25,"category_name":29,"show_sort_weight":112,"slug":113},8,30,"research-report",{"id":115,"doc_module":4,"doc_module_name":25,"category_name":116,"show_sort_weight":117,"slug":118},9,"Religion & 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Cup","world-cup",{"id":123,"doc_module":4,"doc_module_name":25,"category_name":124,"show_sort_weight":123,"slug":125},10,"Lifestyle","lifestyle",{"id":127,"doc_module":4,"doc_module_name":25,"category_name":128,"show_sort_weight":55,"slug":129},19,"General","general",{"code":4,"msg":82,"data":131},{"doc_id":79,"user_id":132,"nickname":42,"user_avatar":133,"doc_module":4,"category_id":111,"category_name":29,"doc_title":10,"doc_description":12,"doc_content":134,"file_id":135,"file_url":136,"file_type":137,"file_size":138,"view_count":55,"is_deleted":4,"is_public":22,"is_downloadable":22,"audit_status":22,"page_count":139,"language":140,"language_code":8,"site_id":7,"html_lang":8,"table_of_contents":141,"faqs":142,"seo_title":143,"seo_description":12,"update_tm":80,"read_time":144},8796095027276,"https://avatar.qwps.com/avatar/d3BzX2FwX3Rlc3RfMjUxMTI2XzAxODA=","PPPL-3145-Preprint Date: October 1995, UC-420, 426, 427  \nAlpha-Physics and Measurement Requirements for ITER  \nS.J. Zweben\\#, S. Putvinski *, M. P. Petrov†,  \nG. Sadler+, K. Tobita¶, and K.M. Young\\#  \n\\# Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, NJ 08540 USA  \n* ITER Joint Central Team, La Jolla, Calif. 92037 USA  \n† Ioffe Physical-Technical Institute, St. Petersburg, 194021 Russia  \n+ JET Joint Undertaking, Abingdon, Oxfordshire, United Kingdom  \n¶ JAERI, Naka-machi, Naka-gun, Ibaraki, 311-01, Japan  \nAbstract  \nThis paper reviews alpha particle physics issues in ITER and their implications for alpha particle measurements. A comparison is made between alpha heating in ITER and NBI and ICRH heating systems in present tokamaks, and alpha particle issues in ITER are discussed in three physics areas: “single particle” alpha effects,“collective” alpha effects, and RF interactions with alpha particles.  \nPaper presented at the ITER Diagnostics Workshop Varenna, Italy Aug. 28-Sept. 1, 1995  \n1. INTRODUCTION  \nSustained ignition in ITER requires about 300 MW of alpha particle heating power. Since the alpha particle creation rate will depend strongly on the plasma conditions, this plasma heating will be more difficult to predict and control than existing heating systems such as NBI and ICRH. In addition, alpha particle heating and loss will also depend upon the transport of alphas during their relatively long thermalization time (≈ 1 sec), during which they may be affected by MHD activity and other nonaxisymmetries in the ignited plasma.  \nThis paper reviews alpha particle physics issues in ITER and their implications for alpha particle measurements. First, a comparison is made between alpha heating in ITER and NBI and ICRH heating systems in present tokamaks. Then the alpha particle issues in ITER will be discussed in three physics areas: “single particle” alpha effects, “collective” alpha effects, and RF interactions with alpha particles. Note that this paper will not cover the important subject of alpha particle ash, which is more related to thermal plasma transport.  \n2. ALPHA HEATING IN ITER vs. PRESENT FAST ION HEATING SYSTEMS  \nThe fast ions used for NBI and ICRH minority heating in present experiments have not been diagnosed in great detail, since they usually heat the plasma without problems[1] . It is interesting to compare the parameters for these fast ion heating systems with those expected for alpha particle parameters in ITER to help identify potential problem areas and appropriate alpha particle measurement requirements. This comparison is shown in Table 1.  \nThe heating power density of alphas in ITER will actually be lower than that for present tokamak heating systems, since the plasma energy density will be only slightly larger, but the plasma energy loss rate will be lower. Thus the relative alpha particle density in ITER is typically an order of magnitude lower than the fast ion density in NBI[2] and ICRH[3] heated tokamaks, also in part due to the larger alpha particle energy. The alpha particle beta in ITER is also expected to be smaller than the fast ion betas normally obtained with present auxiliary-heated large tokamaks[2,3], but somewhat larger than presently obtained for alphas in the TFTR DT experiment[4] .  \nThe similarity of the fast ion orbit parameter ∂/a and the fast ion pressure gradient R∇β fbetween NBI in TFTR and alphas in ITER suggests that the single-particle and collective fast ion physics should also be similar. However, a crucial difference is that the fast ion speed relative to the Alfven speed Vfo/VAlf is much larger for alphas in ITER than for NBI in TFTR, leading to the possibility of Alfven instabilities in ITER[5-7] . Although super-Alfvenic fast ions were simulated by ICRH minority heating in JET, these ions were mainly trapped particles and so were potentially different from thenearly isotropic alpha distributions expected in ITER.  \nIf the single-particle and col","cbCaitOd0JT7PhUY","https://ap.wps.com/l/cbCaitOd0JT7PhUY","pdf",151510,11,"English","# Introduction\n## Alpha heating in ITER vs. present fast ion heating systems\n## “Single particle” alpha interactions","[{\"question\":\"Why is alpha particle heating in ITER harder to predict and control than NBI/ICRH heating?\",\"answer\":\"Alpha particle creation depends strongly on plasma conditions, and heating and loss also depend on alpha transport during their long thermalization time (~1 s) with possible MHD activity and nonaxisymmetries.\"},{\"question\":\"How does ITER alpha heating compare with fast ion heating in present tokamaks?\",\"answer\":\"ITER alpha heating power density is expected to be lower, with alpha particle density typically about an order of magnitude lower than NBI fast-ion density, and an ITER alpha beta smaller than most auxiliary-heated tokamak values.\"},{\"question\":\"What are the main physics areas used to discuss alpha particle issues in ITER?\",\"answer\":\"The paper discusses three areas: single-particle alpha effects, collective alpha effects, and RF interactions with alpha particles.\"}]","Alpha-Physics and Measurement Requirements for ITER - Preprint | PDF",28]