Articolo in rivista, 2021, ENG, 10.1016/j.fusengdes.2021.112424

Development of a set of movable electrostatic probes to characterize the plasma in the ITER neutral beam negative-ion source prototype

Sartori E.; Brombin M.; Laterza B.; Zuin M.; Cavazzana R.; Cervaro V.; Degli Agostini F.; Fadone M.; Fasolo D.; Grando L.; Jain P.; Kisaki M.; Maistrello A.; Moro G.; Pimazzoni A.; Poggi C.; Segalini B.; Shepherd A.; Spolaore M.; Taliercio C.; Tollin M.; Ugoletti M.; Veltri P.; Zamengo A.; Serianni G.

Consorzio RFX (CNR, ENEA, INFN, UNIPD, Acciaierie Venete SpA), Padova, Italy; CNR ISTP, Istituto per la Scienza e Tecnologia dei Plasmi, Sede di Padova, Italy; National Institute for Fusion Science, National Institutes of Natural Sciences, Toki, Japan; Università degli studi di Padova, Italy; CCFE, Culham Science Centre, Abingdon, Oxon, UK; ITER Organization, St. Paul-lez-Durance, France.

We present the development and first use of a set of movable electrostatic probes on the full-scale ITER heating neutral beam prototype negative-ion source SPIDER. The probes access the ion source plasma from the multi-aperture accelerator aiming at the study of the plasma formation and expansion from the RF drivers through the transverse magnetic filter. The magnetic filter separates the relatively high electron-temperature region for plasma formation and hydrogen dissociation form the negative-ion extraction region in which low electron-temperature is required to avoid negative-ion destruction, but also causes non-uniformities and drifts in the large plasma discharge which will be studied by this setup. The set of electrostatic probes encompasses eight RF-compensated Langmuir probes, one double probe, one Mach probe for the assessment of plasma drift velocities, and two gridded retarding field energy analyzers to measure the positive-ion energy distribution function. Electric aspects as well as mechanical constraints given by the large in-vacuum movable structure, and thermal requirements of these relatively heat-flux components made the design challenging. Prototyping and commissioning of the measurement system is discussed offering examples of measured characteristics with the various probes.

Fusion engineering and design (Print) 169 , pp. 112424-1–112424-7

Keywords

Electrostatic probes, Beam sources, Negative ions, ITER heating neutral beam injector

CNR authors

Cervaro Vannino, Taliercio Cesare, Serianni Gianluigi, Grando Luca, Spolaore Monica, Zuin Matteo, Brombin Matteo, Degli Agostini Fabio

CNR institutes

ISTP – Istituto per la Scienza e Tecnologia dei Plasmi

ID: 450287

Year: 2021

Type: Articolo in rivista

Creation: 2021-03-30 09:03:19.000

Last update: 2022-09-21 16:54:12.000

External IDs

CNR OAI-PMH: oai:it.cnr:prodotti:450287

DOI: 10.1016/j.fusengdes.2021.112424

Scopus: 2-s2.0-85102843208

ISI Web of Science (WOS): 000672578400009