title: Fast imaging diagnostics on the C-2U advanced beam-driven field-reversed configuration device.
abstract: The C-2U device employed neutral beam injection, end-biasing, and various particle fueling techniques to sustain a Field-Reversed Configuration (FRC) plasma. As part of the diagnostic suite, two fast imaging instruments with radial and nearly axial plasma views were developed using a common camera platform. To achieve the necessary viewing geometry, imaging lenses were mounted behind re-entrant viewports attached to welded bellows. During gettering, the vacuum optics were retracted and isolated behind a gate valve permitting their removal if cleaning was necessary. The axial view incorporated a stainless-steel mirror in a protective cap assembly attached to the vacuum-side of the viewport. For each system, a custom lens-based, high-throughput optical periscope was designed to relay the plasma image about half a meter to a high-speed camera. Each instrument also contained a remote-controlled filter wheel, set between shots to isolate a particular hydrogen or impurity emission line. The design of the camera platform, imaging performance, and sample data for each view is presented.
authors.affiliation: Tri Alpha Energy, P.O. Box 7010, Rancho Santa Margarita, California 92688, USA.
authors.forename: E M
authors.initials: EM
authors.lastname: Granstedt
authors.affiliation: Tri Alpha Energy, P.O. Box 7010, Rancho Santa Margarita, California 92688, USA.
authors.forename: P
authors.initials: P
authors.lastname: Petrov
authors.affiliation: Tri Alpha Energy, P.O. Box 7010, Rancho Santa Margarita, California 92688, USA.
authors.forename: K
authors.initials: K
authors.lastname: Knapp
authors.affiliation: Tri Alpha Energy, P.O. Box 7010, Rancho Santa Margarita, California 92688, USA.
authors.forename: M
authors.initials: M
authors.lastname: Cordero
authors.affiliation: Tri Alpha Energy, P.O. Box 7010, Rancho Santa Margarita, California 92688, USA.
authors.forename: V
authors.initials: V
authors.lastname: Patel