title: First results of the SOL reflectometer on Alcator C-Mod.
abstract: A swept-frequency X-mode reflectometer has been built on Alcator C-Mod to measure the scrape-off layer (SOL) density profiles adjacent to the lower hybrid launcher. The reflectometer system operates between 100 and 146 GHz at sweep rates from 10 μs to 1 ms and covers a density range of ∼10(16)-10(20) m(-3) at B(0) = 5-5.4 T. This paper discusses the analysis of reflectometer density profiles and presents first experimental results of SOL density profile modifications due to the application of lower hybrid range-of-frequencies power to L-mode discharges. Comparison between density profiles measured by the X-mode reflectometer and scanning Langmuir probes is also shown.
authors.affiliation: MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA. cornwall@mit.edu
authors.forename: C
authors.initials: C
authors.lastname: Lau
authors.forename: G
authors.initials: G
authors.lastname: Hanson
authors.forename: Y
authors.initials: Y
authors.lastname: Lin
authors.forename: J
authors.initials: J
authors.lastname: Wilgen
authors.forename: S
authors.initials: S
authors.lastname: Wukitch
authors.forename: B
authors.initials: B
authors.lastname: Labombard
authors.forename: G
authors.initials: G
authors.lastname: Wallace