A study of the vacuum magnetic field produced by the Poloidal Field (PF) coil system of ASDEX Upgrade is presented. In the model both coils and their power-supply feedthroughsare considered. The latter contribute to the error fields (EFs) that have already been observed and reported in [1, 2]. The effect on the Bfield due to PF coils, assumed to be perfectly axisym-metric, is addressed by analytical formulas, while a 1-D model is applied to feedthroughs [3].Figure 1:Bn(values in T) onq=2 sur-face, before (above) and after (below)correction.Figure 2: Virtual shell (blue) and activesaddle coils (yellow).The model is applied to a reference shot (#35352) for the computation of the normal component ofB(i.e.Bn) projected on theq=2 rational surface. The resulting EF patternis located near the feedthroughs region, with a maximumvalue close to 0.25 mT. ASDEX Upgrade is equipped with aset of 16 in-vessel saddle coils [4], that can be used to minimize the effect of EFs on plasma discharges. A preliminary correction strategy of the non-axisymmetric field generated by feedthroughs is based on a Virtual Shell Approach, that is made up by 8 upper and 8 lower saddle loops built ontheq=2 surface. The matrixM16\u00d716of the mutual inductances between active coils and virtual shell is computed nu-merically, such thatI=M-1???, where???is the vector of the fluxes linked by the virtual shell loops and Istores the unknown currents needed for compensating those fluxes. A more detailed analysis is foreseen to include further possible sources of EFs(e.g. passive conductive structures, ferromagnetic tiles, tilting of PF coils). Moreover, MARS-F[5] can be used for calculations of plasma response to a prescribedm, nharmonic of the EFdistribution, and a new correction strategy may be applied for reducing the resulting EF pattern.<\/p>\n","protected":false},"excerpt":{"rendered":"
Voltolina D.; Bettini P.; Igochine V.; Marrelli L.; McDermott R.; Pigatto L.; Piron L.; Zammuto I.; the ASDEX Upgrade Team; the EUROfusion MST1 Team<\/p>\n","protected":false},"featured_media":1294,"comment_status":"closed","ping_status":"open","template":"","meta":[],"product_cat":[704],"product_tag":[1228,1229],"class_list":["post-6742","product","type-product","status-publish","has-post-thumbnail","hentry","product_cat-conference-proceedings","product_tag-asdex","product_tag-poloidal-field","prodpage-style2"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.istp.cnr.it\/it\/wp-json\/wp\/v2\/product\/6742","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=6742"}],"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=6742"}],"wp:term":[{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/www.istp.cnr.it\/it\/wp-json\/wp\/v2\/product_cat?post=6742"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/www.istp.cnr.it\/it\/wp-json\/wp\/v2\/product_tag?post=6742"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}