Magnetic-Electrostatic Confinement Fusion Energy

1. Magnetic-Electrostatic Confinement Fusion Energy Daniel J. Bateman University of Washington, Seattle WA Devlin R. Baker Western Washington University, Bellingham WA

2. Outline • Primary Fusion Energy Research •Magnetic Confinement • Inertial Confinement • Electrostatic Confinement • Polywell System (Electrons Injected) • Magnetic-Electrostatic Confinement • Conclusions

3. Magnetic Confinement Construction scheduled to begin in 2009 First plasma scheduled for 2016 Goal: Produce 400-500MW output from 40MW input G>10 Will not produce useable power ITER - $1010

4. Inertial Confinement Estimated to be completed in 2009 First ignition tests scheduled for 2010 Will not produce useable power National Ignition Facility (NIF) - $109

5. Electrostatic Confinement • University of Wisconsin Madison • Univeristy of Illinois at Urbana-Champaign • Hobbyists, Science Fair, etc. IEC - from $103 • Steady State • Not for energy production

6. How Does Electrostatic Confinement Work? • If inner grid is positive: electron acceleration device (EXL) • If inner grid is negative: ion acceleration device (IXL) • First paper (1959 Elmore et al.) was on EXL • First experiments (Hirsch & Farnsworth) were on EXL • EXL devices create negative electrostatic potential well which accelerate ions to the center of the sphere • Grid losses prevent net energy gain • Increasing grid transparency decreases structural integrity Electron Acceleration (EXL) Device

7. Ions Impinging Radially Inward Do Not Satisfy the Center of Mass Frame Reaction Rates Reaction rate:

8. Magnetic-Electrostatic Confinement: The Polywell Device Uses a Magnetic Grid • Electromagnets become inner grid – both the outer shells and the inner coils are charged to high potential (15kV min) • Shape of electromagnets must be conformal to magnetic field • Box coils were used from mid 1990’s to 2004 with poor results • Coil spacing to provide point cusp magnetic field at each corner

9. Background of the Polywell Device • Proposed by Robert W. Bussard in 1985 • Analysis by Nicholas A. Krall with first paper published 1992 • Krall & Rosenberg paper 1992 shows that ion-ion Maxwellianization in the edge region helps to maintain primarily radial ion flow in the interior

10. Collisionality Three distinct regions exist for both electrons and ions Electrons: • Central region: Electrons at lowest energy, Maxwellian Approximately constant charge density • Wiffleball: Primarily radial velocity distribution Inverse-square of radius density dependence High B gradient boundary reflection • Edge: Electrons at high energy Escaping electrons recirculate through cusp current • Core: Ions at highest energy, non-Maxwellian Extremely low time-in-region • Bulk: Primarily radial velocity distribution, minimal collisions • Edge: Ions at lowest energy Large time-in-region, high collisionality Ions:

11. Conclusions: • Inertial-electrostatic confinement is an effective means of initiating and sustaining nuclear fusion reactions. • Grid losses prevent net energy gain. • MHD stable polyhedral magnetic grid: •reduces grid losses • provides additional electron confinement. • Ions introduced near system radius begin with radial oscillations in the well. • Collisional effects in must be considered within distinct regions. • Edge collisions dominate interior collisions, which help to maintain primarily radial flow

12. Questions?