title: Evaluation of plasma-based transmit coils for magnetic resonance.
abstract: In this work a new concept for designing transmit coils for magnetic resonance using a plasma is introduced. Unlike conventional coils, a plasma can be turned on and off, eliminating electrical interactions between coils, and enabling radiofrequency-invisibility when desired. A surfatron has been designed to produce a surface-mode wave which propagates along the inner surface of a commercial fluorescent lighting tube. NMR spectra and images have been produced using the plasma as the transmit coil and a copper-based monopole to receive the signal. The transmit efficiency of the plasma tube was estimated, and is currently much lower than that of an equivalently-sized metal-based structure: however, there are many potential methods for increasing the efficiency using a custom-built plasma tube.
authors.affiliation: C.J. Gorter Center for High Field MRI, Leiden University Medical Center, The Netherlands. Electronic address: a.webb@lumc.nl.
authors.forename: A G
authors.initials: AG
authors.lastname: Webb
authors.affiliation: C.J. Gorter Center for High Field MRI, Leiden University Medical Center, The Netherlands; NORAS MRI products GmbH, Leibnizstrasse 4, 97204 Hoechberg, Germany.
authors.forename: S A
authors.initials: SA
authors.lastname: Aussenhofer
keywords: Monopole; Plasma; Plasma frequency; Reconfigurable RF coil; Transmit efficiency