title: A double-layer based model of ion confinement in electron cyclotron resonance ion source.
abstract: The paper proposes a new model of ion confinement in ECRIS, which can be easily generalized to any magnetic configuration characterized by closed magnetic surfaces. Traditionally, ion confinement in B-min configurations is ascribed to a negative potential dip due to superhot electrons, adiabatically confined by the magneto-static field. However, kinetic simulations including RF heating affected by cavity modes structures indicate that high energy electrons populate just a thin slab overlapping the ECR layer, while their density drops down of more than one order of magnitude outside. Ions, instead, diffuse across the electron layer due to their high collisionality. This is the proper physical condition to establish a double-layer (DL) configuration which self-consistently originates a potential barrier; this "barrier" confines the ions inside the plasma core surrounded by the ECR surface. The paper will describe a simplified ion confinement model based on plasma density non-homogeneity and DL formation.
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Mascali
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Neri
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Celona
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Castro
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Torrisi
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Gammino
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Sorbello
authors.affiliation: Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Ciavola