SITIS Archives - Topic Details
Program:  SBIR
Topic Num:  AF071-007 (AirForce)
Title:  High Voltage Explosive Flux Compression Generators
Research & Technical Areas:  Ground/Sea Vehicles, Sensors, Electronics

  Objective:  Increase internal voltage tolerance of explosive flux compression generators (FCGs). This means develop improved modeling of internal FCG voltages and concepts to increase voltage tolerance.
  Description:  Development of ability to greatly increase internal voltage tolerance of explosive flux compression generators (FCGs), particularly helical FCGs. One of the most serious limitations of explosively driven magnetic flux compression generators is voltage tolerance. That is, virtually all flux compression generators must be designed to operate within a relatively modest voltage, and hence electric field, range. The range of operating voltages has been found empirically to be considerably below the ranges one would expect for laboratory pulsed power devices that use standard solid and gas dielectric insulation. The typical maximum output terminal voltage for megajoule-class generators is about 50 kilovolts, corresponding to an internal equivalent source voltage of approximately 160 kilovolts. For typical armature-stator gaps of 10 centimeters, the output voltage represents a maximum electric field stress of only 5 kilovolts per centimeter (kV/cm), whereas the air breakdown field stress is approximately 40 kV/cm and approximately 100 kV/cm for sulfur hexafluoride (SF6). At this time, it is not known why FCGs are so voltage intolerant, but the limitation translates directly to larger sizes than what one could use if higher stresses could be tolerated. Furthermore, for a given inductive load, the maximum output terminal voltage dictates the maximum rate of current rise, which is often desired to be higher than that currently achievable. For this topic, this means develop improved ability to model internal FCG voltages, as well as develop concepts for increasing FCG tolerance to such voltages.

  PHASE I: Requires innovative research and development of modeling of FCG internal voltages and concepts to greatly increase their voltage tolerance.
  
  PHASE II: Develop a feasible concept for greatly increasing FCG internal voltage tolerance, implement a significant part of the new concept. Develop a business and commercialization plan for the Phase II engineering development and marketing program.

  DUAL USE COMMERCIALIZATION: Military application: Military uses of this technology include very compact portable pulsed power for high current uses, such as radiation sources. Commercial application: Possible civilian sector applications include radiation sources, seismic probes, lightning simulators for Homeland Defense, law enforcement, public safety, oil prospecting, and counter mine systems.

  References:  1. Megagauss Conference Proceedings I through X provide good information on FCG technology. 2. H.Knoepfel, "Pulsed High Magnetic Fields," North Holland Publishing Co, Amsterdam, London, p.87 (1970).

Keywords:  internal voltage tolerance, explosive flux compression generator, FCG, megajoule

Questions and Answers:
Q: 1. Is achieving high voltages a primary concern for this topic?
2. Would the agency be open to other avenues of generating high voltage off of high explosives?
3. Why does the agency need high voltages?
4. Is this connected to any other project? If so, which project?
5. Can I have access to the the research developed by the project?
6. Which is more important high voltages or high current
7. How would this source of power be superior to current high voltage systems such as capacitors?
8. Can you please clarify why homeland security needs lightning simulators?
9. How would pulsed power systems aid in oil prospecting and counter mine systems?
A: 1. - 3. The reason for desiring higher internal voltage and output voltage operational ability is to deliver higher currents to inductive loads without increasing current risetime.

4. This effort is to increase general FCG capability, which is a USAF 6.2 effort.

5. No, not at this time.

6. The reason for desiring higher internal voltage and output voltage operational ability is to deliver higher currents to inductive loads without increasing current risetime.

7. An FCG system will be more compact, and more readily scalable to higher energy and current without such large capital costs or design inflexibility.

8. It is reasonable to expect DHS to be interested in such things, but I do not have specific knowledge of the extent to which they are.

9. The Russians have reported on injecting current into the ground as a diagnostic for several things, including earthquake prediction and prospecting. This, as well as many FCG features, is mentioned in some Megagauss Conference Proceedings papers (Conference years 1979, 1983, 1986, 1989, 1992, 1996, and 2002). This, as well as many FCG features, may also be mentioned by the Russians in IEEE Pulsed Power Proceedings papers since 1991.
Q: 1. Is achieving high voltages a primary concern for this topic?
2. Would the agency be open to other avenues of generating high voltage off of high explosives?
3. Why does the agency need high voltages?
4. Is this connected to any other project? If so, which project?
5. Can I have access to the the research developed by the project?
6. Which is more important high voltages or high current
7. How would this source of power be superior to current high voltage systems such as capacitors?
8. Can you please clarify why homeland security needs lightning simulators?
9. How would pulsed power systems aid in oil prospecting and counter mine systems?
A: 1. - 3. The reason for desiring higher internal voltage and output voltage operational ability is to deliver higher currents to inductive loads without increasing current risetime.

4. This effort is to increase general FCG capability, which is a USAF 6.2 effort.

5. No, not at this time.

6. The reason for desiring higher internal voltage and output voltage operational ability is to deliver higher currents to inductive loads without increasing current risetime.

7. An FCG system will be more compact, and more readily scalable to higher energy and current without such large capital costs or design inflexibility.

8. It is reasonable to expect DHS to be interested in such things, but I do not have specific knowledge of the extent to which they are.

9. The Russians have reported on injecting current into the ground as a diagnostic for several things, including earthquake prediction and prospecting. This, as well as many FCG features, is mentioned in some Megagauss Conference Proceedings papers (Conference years 1979, 1983, 1986, 1989, 1992, 1996, and 2002). This, as well as many FCG features, may also be mentioned by the Russians in IEEE Pulsed Power Proceedings papers since 1991.

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