MURI Conference Working Group

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UNM Consortium Overview Compact Pulsed Power
for High Power Microwaves First Annual Review
of FY2001 AFOSR/DoD MURI Program Edl
Schamiloglu, Gardner-Zemke Professor,
PI Department of Electrical and Computer
Engineering University of New Mexico Albuquerque,
NM 87131 USA edl_at_eece.unm.edu
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Compact Pulsed Power MURI
Consortium Lead Professor Edl Schamiloglu,
UNM Consortium Partner Professor Karl
Schoenbach, Old Dominion University Consortium
Partner Dr. Robert Vidmar, University of Nevada,
Reno Consortium Affiliates Sandia National
Laboratories (Gerald Yonas), Los Alamos National
Laboratory (Mike Fazio), Air Force Research
Laboratory (DE Directorate), Lockheed Martin
Aeronautics Company (Steve Calico), and
Diversified Technologies, Inc. (Marcel
Gaudreau). Program Began 1 June 2001, 1 M/year
for up to 5 years.
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DEFINITIONS
High Power Microwaves imprecise term, usually
denotes sources of coherent radiation spanning 1
GHz - gt100 GHz at power levels scaling as Pf 2
driven by high-perveance, relativistic electron
beams. Pulsed Power - imprecise term, typically
denotes the combination of a capacitive energy
storage system that is charged over a long
period of time (time scale seconds), and that is
rapidly switched to yield a high power pulse
that is tailored and better matched to a load
using a pulse forming line (final pulse width in
nanosecond to microsecond range). Pulsed Power
is the technology used to generate the
high-perveance beams to drive HPM sources.
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ALTERNATE MEANINGS
High Power Microwaves a) can mean high average
power sources. A 10 kW average power tube is
considered high power. A 100 kW pulsed
power-driven tube is not very high power. b)
can mean high power ultra-wideband microwave
sources (not coherent, but broadband). Pulsed
Power - a) can mean rapidly switched solid state
components, typically used to drive
ultra-wideband sources. b) can include chemical
explosive-generated voltage pulses (explosive
flux compression generators).
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History of HPM Linked to History of Pulsed Power
High Power Microwaves born in late 1960s and
early 1970s Prof. John Nation (Cornell
University) and Drs. Petelin, Kovalev
(Institute of Applied Physics, Gorky - Nizhny
Novgorod, USSR, in collaboration with group in
Moscow). Pulsed Power modern pulsed power
attributed to Charlie Martin and colleagues at
AWRE, Aldermaston in England in 1960s. Group
interested in radiography had to use pulsed
power to increase doses. Initial HPM sources
revisited traditional microwave tubes, except
used intense beams to drive them. Professor
Kovalev is Visiting Professor of EECE, June-July,
2002
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How Do We Place HPM Pulsed Power in an
Academic Context?

• As an academic discipline, our research falls
  within the field of
• High Energy Density (Plasma Physics) Research
  (see National Academy of Sciences study, led by
  Ron Davidson, in progresshttp//www.nas.edu/bpa/p
  rojects/hedpp/rd.pdf)
• Inertial Confinement Fusion
• X-Ray and Gamma-Ray Radiation Sources
• Plasma Accelerators
• High Power Microwaves
• Why is there Interest in High Energy Density
  Research?
• Stockpile Stewardship (DoE radiation sources
  and ICF)
• Threats to the Infrastructure (General
  e-bomb)
• Fusion Energy Research (DoE alternate energy
  source)
• Directed Energy Weapons (DoD chemical lasers,
  HPM)

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UNM is Located at the Hub of Pulsed Power
Research in the United States
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What Goes Around, Comes Around
Old
Pulsed Power
Electrodynamic Structure
Beams
New
Our present focus new materials, sophisticated
diagnostics, better modeling
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Pulsed Power
Capacitive Energy Storage Systems are Typically
Large and Massive, but Basic Research can Lead to
More Compact Devices
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What Is Required To Achieve This?
NOTE In the following slides for items with
check mark, BLUE type indicates work in progress,
BLACK type indicates work to begin in future

• Basic Research In
• Compact Pulsed Power Topologies (Folded Blumlein
  Pulsers Attractive Research Ceramics and
  Liquids Support AFRL/SNL Research)

?
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What Is Required To Achieve This?
Compact folded Blumlein pulse-shaping driver at
Sandia National Laboratories Courtesy Ron Pate
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What Is Required To Achieve This?
48-inch Blumlein folded into a 15
assembly Courtesy Ron Pate
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What Is Required To Achieve This?
Rail gap switch assembly Courtesy Ron Pate
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What Is Required To Achieve This?
Electrostatic calculation of voltage contours at
edge of Blumlein. Breakdown at the edge a
problem.
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What Is Required To Achieve This?
TOP Closure of resistive grading channel in edge
region due to flaring of adjacent cells.
BOTTOM Edge support modified to maintain open
channel to facilitate resistive grading.
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Summary of Challenges in Compact Pulser
Development

• Prebreakdown problems with propylene carbonate.
  Why does bubbling precede any sign of corona?
  What can be done to prevent this?
• Desire to move to ceramic dielectrics (Egt400
  kV/cm, dielectric constants gt100)
• Problems with rail gap switches need improved
  performance

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What Is Required To Achieve This?

• Basic Research In
• Improved Understanding of Breakdown in Solid and
  Liquid Dielectrics (Time-Dependent)

Photographs of prebreakdown phenomena in tap
water between a tip and plate. The gap is 100 µm,
the applied voltage 2 kV. Exposure time is 10 ns.
The first photograph shows the gap at 27 µs after
pulse application. Micro bubbles are formed at
the tip. 10 µs later (lower photograph) plasma
formation is observed at the location of the air
micro-bubbles, and shockwaves are emitted from
the plasma centers. (Courtesy Karl Schoenbach,
Old Dominion University.)
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What Is Required To Achieve This?

• Basic Research In
• Use of Electromagnetic Simulation Tools in Design
  of Systems

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What Is Required To Achieve This?

• Basic Research In
• High Pressure Liquid and Gas Switches

• Critical to
• Transmitter for high power, ultra-wideband
  requires large dV/dt for fixed antenna aperture
  height
• Much data exists
• University of Strathclyde has data on variety of
  dielectrics and fast pulse breakdown. UNM/Sandia
  to analyze. Problem? Relate parameters at point
  of measurement to arc region.

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What Is Required To Achieve This?

• Basic Research In
• Tapered Transmission Lines with Microchannel
  Cooling
• Thermal Management in Pulsed Power Systems

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What Is Required To Achieve This?

• Basic Research In
• Compact Pulsed Power Systems using Advanced
  Components (IGBTs, MOSFETS, etc.)

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(Slide Courtesy of Dr. Mike Fazio, LANL)
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(Slide Courtesy of Dr. Mike Fazio, LANL)
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What Is Required To Achieve This?

• Basic Research In
• Behavior of Liquid Dielectrics in High Altitude
  Environment
• Developing Connectors for High Current Pulsed
  Power Applications

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UNM CP3 MURI SYNERGISTIC RELATIONS June
2002
Karl Schoenbach Edl
Schamiloglu
Robert Vidmar Old Dominion University
University of New Mexico University of
Reno - Nevada
Tapered Trans. Lines R. Vidmar (UNR)
Fieldable HPM Systems K. Hackett (AFRL/DEHA) W.
Prather (AFRL/DEHP T. Spencer (AFRL/DEHP) C.
Woods (AFRL/DEHA)
DoD Panel R.J. Barker,AFOSR/NE P. Turchi, AFRL A.
Kehs, ARL B. Ganguly, AFRL J. Sethian, NRL G.
Cooperstein, NRL R. Gullickson, DTRA
COMPACT, PORTABLE, PULSED POWER
SS Switches LANL IGBTs
UM-Col. - PCSS
Dielectric Breakdown
SEE UNM (Manasreh) Calabazos Creek
Blumlein Technology E. Schamiloglu, C.
Christodoulou, J. Gaudet (UNM)
Liquid Breakdown K. Schoenbach R. Joshi (ODU)
Transient Breakdown S. Tyo (UNM)
International U. of Strathcylde (U.K.) IRI -
Saitama U. (Japan) IRI - QinetiQ (U.K.)
DEPSCoR D. Evans (UNM/Chem)
ASR
SNL
UM-Rolla
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Schedule
245 PM UNM Consortium Overview Edl
Schamiloglu, UNM Compact Pulsed Power for High
Power Microwaves   Old Dominion
University 300 PM Liquid Breakdown
Studies Karl Schoenbach 320 PM Modeling of
Liquid Breakdown Ravi Joshi   University of
Nevada Reno 330 PM Tapered Transmission
Lines Robert Vidmar University of New
Mexico 340 PM Electromagnetic Modeling for
Fast Scott Tyo Switches in Liquids/Gases 350
PM Comprehensive Study of Folded Edl
Schamiloglu Blumlein Pulsers EM
Modeling, Materials, and Switches switching
with IGBTs 420 PM Summary and Year 2
Plans Edl Schamiloglu