TY - GEN
T1 - Delay time reduction of high power microwave surface flashover using metallic initiators
AU - Foster, J.
AU - Krompholz, H.
AU - Neuber, A.
PY - 2010
Y1 - 2010
N2 - High power microwave (HPM) surface flashover can be rapidly induced by introducing metallic points on to the dielectric surface with negligible effect on the transmission properties. An experimental setup comprised of a magnetron operating at 2.85 GHz to produce a 4.5 MW, 3 s pulse is used for observing surface flashover in various atmospheric conditions. An active pulse sharpening mechanism is used to reduce the pulse rise time in order to apply the electric field in tens of nanoseconds. For a system in which HPM transmission must be quickly suppressed, field enhancing geometries can provide a way for flashover to develop rapidly while keeping insertion loss at a minimum (<0.01 dB). Initial experiments utilizing 0.2 mm2 aluminum points with a spatial density of 25/cm2 have increased the global effective electric field by a factor of ∼1.5. This increase in electric field has sharply reduced delay times for surface flashover (i.e. the time between the application of the HPM pulse and a sharp drop in transmitted power). For an environment consisting of air at 155 torr, for instance, the delay time is reduced from 455 ns to 101 ns. Presented in this paper is a comparison of various field-enhancing geometries and how they relate to flashover development. Also, an analysis of time resolved images will be given along with an estimation of field enhancement factors.
AB - High power microwave (HPM) surface flashover can be rapidly induced by introducing metallic points on to the dielectric surface with negligible effect on the transmission properties. An experimental setup comprised of a magnetron operating at 2.85 GHz to produce a 4.5 MW, 3 s pulse is used for observing surface flashover in various atmospheric conditions. An active pulse sharpening mechanism is used to reduce the pulse rise time in order to apply the electric field in tens of nanoseconds. For a system in which HPM transmission must be quickly suppressed, field enhancing geometries can provide a way for flashover to develop rapidly while keeping insertion loss at a minimum (<0.01 dB). Initial experiments utilizing 0.2 mm2 aluminum points with a spatial density of 25/cm2 have increased the global effective electric field by a factor of ∼1.5. This increase in electric field has sharply reduced delay times for surface flashover (i.e. the time between the application of the HPM pulse and a sharp drop in transmitted power). For an environment consisting of air at 155 torr, for instance, the delay time is reduced from 455 ns to 101 ns. Presented in this paper is a comparison of various field-enhancing geometries and how they relate to flashover development. Also, an analysis of time resolved images will be given along with an estimation of field enhancement factors.
UR - http://www.scopus.com/inward/record.url?scp=80051710801&partnerID=8YFLogxK
U2 - 10.1109/IPMHVC.2010.5958313
DO - 10.1109/IPMHVC.2010.5958313
M3 - Conference contribution
AN - SCOPUS:80051710801
SN - 9781424471294
T3 - Proceedings of the 2010 IEEE International Power Modulator and High Voltage Conference, IPMHVC 2010
SP - 137
EP - 140
BT - Proceedings of the 2010 IEEE International Power Modulator and High Voltage Conference, IPMHVC 2010
T2 - 2010 IEEE International Power Modulator and High Voltage Conference, IPMHVC 2010
Y2 - 23 May 2010 through 27 May 2010
ER -