{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,12]],"date-time":"2026-02-12T07:57:34Z","timestamp":1770883054300,"version":"3.50.1"},"reference-count":5,"publisher":"AIP Publishing","issue":"1","content-domain":{"domain":["pubs.aip.org"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[1999,1,1]]},"abstract":"<jats:p>The broadband microwave reflectometry system on ASDEX Upgrade has been recently upgraded with new channels. It has now 12 channels that probe simultaneously the high and low fields plasma, with ultrafast sweeping (20\u2013100 \u03bcs). X mode (33\u201375 GHz) is used for the scrape off layer, and the O mode (16\u2013110 GHz) is reflected from densities between 0.3\u00d71019 and 1.5\u00d71019\u200am\u22123. A fast sweeping heterodyne system was developed for the highest frequency channels (50\u2013110 GHz) to cope with higher losses and lower incident power. Fixed frequency operation is employed for fluctuation measurements. A dedicated channel (33\u201355 GHz) operating in fixed frequency provides a signal to continuously monitor the level of density fluctuations (e.g., L\u2013H transition), during the whole discharge. The diagnostic is fully operated by remote control. The acquisition system is based on specially developed VME boards with up to 1 Gsamp\/s sampling rates. Automatic profile inversion was recently implemented using data validation and rejection algorithms. Experimental results are presented to illustrate the profile measurements with O mode and with O and X mode combined operation. We present density profiles measured in a wide range of plasma regimes. Profile modifications due to rotating magnetic islands illustrates the potentialities of the reflectometry to estimate the location of the rational q surfaces.<\/jats:p>","DOI":"10.1063\/1.1149439","type":"journal-article","created":{"date-parts":[[2002,7,26]],"date-time":"2002-07-26T12:04:50Z","timestamp":1027685090000},"page":"1072-1075","update-policy":"https:\/\/doi.org\/10.1063\/aip-crossmark-policy-page","source":"Crossref","is-referenced-by-count":43,"title":["Microwave reflectometry diagnostic for density profile and fluctuation measurements on ASDEX Upgrade"],"prefix":"10.1063","volume":"70","author":[{"given":"A.","family":"Silva","sequence":"first","affiliation":[{"name":"Associa\u00e7\u00e3o EURATOM\/IST-Centro de Fus\u00e3o Nuclear, Instituto Superior T\u00e9cnico, 1096 Lisboa Codex,\u200aPortugal"}]},{"given":"L.","family":"Cupido","sequence":"additional","affiliation":[{"name":"Associa\u00e7\u00e3o EURATOM\/IST-Centro de Fus\u00e3o Nuclear, Instituto Superior T\u00e9cnico, 1096 Lisboa Codex,\u200aPortugal"}]},{"given":"M.","family":"Manso","sequence":"additional","affiliation":[{"name":"Associa\u00e7\u00e3o EURATOM\/IST-Centro de Fus\u00e3o Nuclear, Instituto Superior T\u00e9cnico, 1096 Lisboa Codex,\u200aPortugal"}]},{"given":"F.","family":"Serra","sequence":"additional","affiliation":[{"name":"Associa\u00e7\u00e3o EURATOM\/IST-Centro de Fus\u00e3o Nuclear, Instituto Superior T\u00e9cnico, 1096 Lisboa Codex,\u200aPortugal"}]},{"given":"I.","family":"Nunes","sequence":"additional","affiliation":[{"name":"Associa\u00e7\u00e3o EURATOM\/IST-Centro de Fus\u00e3o Nuclear, Instituto Superior T\u00e9cnico, 1096 Lisboa Codex,\u200aPortugal"}]},{"given":"J.","family":"Santos","sequence":"additional","affiliation":[{"name":"Associa\u00e7\u00e3o EURATOM\/IST-Centro de Fus\u00e3o Nuclear, Instituto Superior T\u00e9cnico, 1096 Lisboa Codex,\u200aPortugal"}]},{"given":"P.","family":"Varela","sequence":"additional","affiliation":[{"name":"Associa\u00e7\u00e3o EURATOM\/IST-Centro de Fus\u00e3o Nuclear, Instituto Superior T\u00e9cnico, 1096 Lisboa Codex,\u200aPortugal"}]},{"given":"S.","family":"Vergamota","sequence":"additional","affiliation":[{"name":"Associa\u00e7\u00e3o EURATOM\/IST-Centro de Fus\u00e3o Nuclear, Instituto Superior T\u00e9cnico, 1096 Lisboa Codex,\u200aPortugal"}]},{"given":"L.","family":"Meneses","sequence":"additional","affiliation":[{"name":"Associa\u00e7\u00e3o EURATOM\/IST-Centro de Fus\u00e3o Nuclear, Instituto Superior T\u00e9cnico, 1096 Lisboa Codex,\u200aPortugal"}]},{"given":"V.","family":"Grossman","sequence":"additional","affiliation":[{"name":"Associa\u00e7\u00e3o EURATOM\/IST-Centro de Fus\u00e3o Nuclear, Instituto Superior T\u00e9cnico, 1096 Lisboa Codex,\u200aPortugal"}]},{"given":"F.","family":"Silva","sequence":"additional","affiliation":[{"name":"Associa\u00e7\u00e3o EURATOM\/IST-Centro de Fus\u00e3o Nuclear, Instituto Superior T\u00e9cnico, 1096 Lisboa Codex,\u200aPortugal"}]},{"given":"C.","family":"Loureiro","sequence":"additional","affiliation":[{"name":"Associa\u00e7\u00e3o EURATOM\/IST-Centro de Fus\u00e3o Nuclear, Instituto Superior T\u00e9cnico, 1096 Lisboa Codex,\u200aPortugal"}]},{"given":"F.","family":"Nunes","sequence":"additional","affiliation":[{"name":"Associa\u00e7\u00e3o EURATOM\/IST-Centro de Fus\u00e3o Nuclear, Instituto Superior T\u00e9cnico, 1096 Lisboa Codex,\u200aPortugal"}]},{"given":"B.","family":"Kurzan","sequence":"additional","affiliation":[{"name":"EURATOM-IPP-Association, Garching,\u200aGermany"}]},{"given":"W.","family":"Suttrop","sequence":"additional","affiliation":[{"name":"EURATOM-IPP-Association, Garching,\u200aGermany"}]}],"member":"317","reference":[{"key":"2024020709540004300_r1"},{"key":"2024020709540004300_r2","doi-asserted-by":"crossref","first-page":"4138","DOI":"10.1063\/1.1147517","volume":"67","year":"1996","journal-title":"Rev. Sci. Instrum."},{"key":"2024020709540004300_r3"},{"key":"2024020709540004300_r4"},{"key":"2024020709540004300_r5","doi-asserted-by":"crossref","first-page":"747","DOI":"10.1088\/0741-3335\/40\/5\/036","volume":"40","year":"1998","journal-title":"Plasma Phys. 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