In recent years, a strong effort has been dedicated to the development of tokamak plasma regimes alternative to the standard high confinement mode (H-mode) with type-I edge localized mode (ELM), i.e. ELM-free and small-ELM regimes, given the associated hardly sustainable energy and particle fluxes on plasma facing components. In this work, we will focus on new H-mode regimes with small-ELMs, the so-called baseline small-ELMs (BSE), characterized by high thermal confinement and low core impurity accumulation, which have been recently found at JET. In order to characterize the micro-turbulence at play at the top of the pedestal, an extensive local linear gyrokinetic analysis with the GKW code has been carried out. In particular, a comparison between a reference type-I ELM (#97395) and two BSE plasmas (#96994 and #94442) has been performed. The ion-scale (0.1 <= k ? ? i <= 2) micro-turbulence is found to have different characteristics in the two regimes. Indeed, kinetic-ballooning modes (KBM) are destabilized in the type-I ELM regime at k ? ? i ~0.1, while they are stable in BSE regimes. In addition, negative (i.e. electron-diamagnetic-direction) frequency modes, identified as electron-temperature-gradient (ETG) modes, are destabilized at k ? ? i ~1.5 in the type-I ELM regime while BSE regimes are characterized by positive (i.e. ion-diamagnetic-direction) frequency modes. Meanwhile, at electron-scale (10 <= k ? ? i <= 700) ETG modes are the dominant micro-instabilities in both regimes. Then, since BSE regimes are characterized by a higher impurity concentration at the pedestal, particular attention has been given to the role played by them. We found that impurities represent a critical player in the linear dynamics, strongly affecting the nature of micro-instabilities at ion-scale.\n<\/p>\n","protected":false},"excerpt":{"rendered":"
Dicorato M.; Muraglia M.; Camenen Y.; Garcia J.; Garbet X.; Frigione D.; Garzotti L.; Lomas P.; Rimini F.; Sozzi C.; Van Eester D.<\/p>\n","protected":false},"featured_media":1294,"comment_status":"closed","ping_status":"open","template":"","meta":[],"product_cat":[704],"product_tag":[806,838,1009,1211,1483,1962,3679],"class_list":["post-9498","product","type-product","status-publish","has-post-thumbnail","hentry","product_cat-conference-proceedings","product_tag-magnetoplasma","product_tag-plasma-simulation","product_tag-plasma-turbulence","product_tag-tokamak-devices","product_tag-electron-temperature","product_tag-plasma-diagnostics","product_tag-plasma-stability","prodpage-style2"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.istp.cnr.it\/it\/wp-json\/wp\/v2\/product\/9498","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.istp.cnr.it\/it\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/www.istp.cnr.it\/it\/wp-json\/wp\/v2\/types\/product"}],"replies":[{"embeddable":true,"href":"https:\/\/www.istp.cnr.it\/it\/wp-json\/wp\/v2\/comments?post=9498"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.istp.cnr.it\/it\/wp-json\/wp\/v2\/media\/1294"}],"wp:attachment":[{"href":"https:\/\/www.istp.cnr.it\/it\/wp-json\/wp\/v2\/media?parent=9498"}],"wp:term":[{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/www.istp.cnr.it\/it\/wp-json\/wp\/v2\/product_cat?post=9498"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/www.istp.cnr.it\/it\/wp-json\/wp\/v2\/product_tag?post=9498"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}