66th Annual Gaseous Electronics Conference
Volume 58, Number 8
Monday–Friday, September 30–October 4 2013;
Princeton, New Jersey
Session PR1: High Pressure Discharges: Dielectric Barrier Discharges, Coronas, Breakdown, Sparks III
1:30 PM–3:00 PM,
Thursday, October 3, 2013
Room: Ballroom I
Chair: David Scott, George Washington University
Abstract ID: BAPS.2013.GEC.PR1.1
Abstract: PR1.00001 : Meter-Scale Atmospheric-Pressure Microwave Plasma Using Sub-Millimeter-Gap Slot*
1:30 PM–2:00 PM
Preview Abstract
Abstract
Author:
Hirotaka Toyoda
(Nagoya University)
Atmospheric-pressure pulsed plasmas have been given much attention because
of its various possibilities for industrial applications such as surface
wettability control, sterilization and so on. Among various
atmospheric-pressure plasma sources, microwave plasma that is produced
inside waveguide-slots is attractive because high-density plasma up to
10$^{15}$ cm$^{-3}$ can be easily produced along very long waveguide with
light-weight and rather simple antenna configuration. So far, we have
investigated plasma production inside slot of the waveguide and in this
talk, elongation of the plasma up to meter-scale with newly-designed plasma
source will be presented.
In this study, two types of antennas are proposed to elongate the
atmospheric-pressure microwave plasma. Firstly, array-structured slot design
with a closed-end waveguide is adopted using X-band microwave (10 GHz). In
this structure, slot antennas with a total number of more than 40 are
positioned with $\lambda_{g}$/2-pitch along $\sim$1m waveguide
so as to utilize standing wave inside the waveguide and to increase the
electric field inside the slot. By optimizing the antenna design, arrayed
microwave plasmas are successfully produced along $\sim$1m-length
waveguide. The arrayed-slot structure, however, the plasma is not completely
uniform along the waveguide and plasma density drastically decreases between
two adjacent slots. To solve this, an alternative type of antenna that is
free from the standing wave effect is designed. In this new-type antenna,
travelling wave inside the waveguide with no reflection wave is realized by
a combination of a microwave circulator and a ring-structured waveguide. By
this transmission line, microwave power flows only to one direction and the
average microwave power becomes spatially uniform along the waveguide. By
using a single but very long slot up to several tens cm, very uniform plasma
is produced along the slot. The result strongly suggests easy scale-up of
the plasma source more than one meter that can be applied to surface
modification of large-scale devices.
*The author thanks Prof. M. Hori, Prof. M. Sekine and Prof. H. Itoh, Nagoya University, for their fruitful discussions.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2013.GEC.PR1.1