title: Limitation of the ECRIS performance by kinetic plasma instabilities (invited).
abstract: Electron cyclotron resonance ion source (ECRIS) plasmas are prone to kinetic instabilities due to anisotropic electron velocity distribution. The instabilities are associated with strong microwave emission and periodic bursts of energetic electrons escaping the magnetic confinement. The instabilities explain the periodic ms-scale oscillation of the extracted beam current observed with several high performance ECRISs and restrict the parameter space available for the optimization of extracted beam currents of highly charged ions. Experiments with the JYFL 14 GHz ECRIS have demonstrated that due to the instabilities the optimum Bmin-field is less than 0.8BECR, which is the value suggested by the semiempirical scaling laws guiding the design of ECRISs.
authors.affiliation: Department of Physics, University of Jyväskylä, 40500 Jyväskylä, Finland.
authors.forename: O
authors.initials: O
authors.lastname: Tarvainen
authors.affiliation: Department of Physics, University of Jyväskylä, 40500 Jyväskylä, Finland.
authors.forename: T
authors.initials: T
authors.lastname: Kalvas
authors.affiliation: Department of Physics, University of Jyväskylä, 40500 Jyväskylä, Finland.
authors.forename: H
authors.initials: H
authors.lastname: Koivisto
authors.affiliation: Department of Physics, University of Jyväskylä, 40500 Jyväskylä, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Komppula
authors.affiliation: Department of Physics, University of Jyväskylä, 40500 Jyväskylä, Finland.
authors.forename: R
authors.initials: R
authors.lastname: Kronholm
authors.affiliation: Department of Physics, University of Jyväskylä, 40500 Jyväskylä, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Laulainen
authors.affiliation: Institute of Applied Physics, RAS, 46 Ul'yanova St., 603950 Nizhny Novgorod, Russian Federation.
authors.forename: I
authors.initials: I
authors.lastname: Izotov
authors.affiliation: Institute of Applied Physics, RAS, 46 Ul'yanova St., 603950 Nizhny Novgorod, Russian Federation.
authors.forename: D
authors.initials: D
authors.lastname: Mansfeld
authors.affiliation: Institute of Applied Physics, RAS, 46 Ul'yanova St., 603950 Nizhny Novgorod, Russian Federation.
authors.forename: V
authors.initials: V
authors.lastname: Skalyga
authors.affiliation: European Organization for Nuclear Research (CERN), 1211 Geneva 23, Switzerland.
authors.forename: V
authors.initials: V
authors.lastname: Toivanen
authors.affiliation: National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA.
authors.forename: G
authors.initials: G
authors.lastname: Machicoane