high energy propulsion
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High Energy Propulsion
Brice CassentiUniversity of Connecticut
High Energy Propulsion
• Fusion• Annihilation• Photon
Fusion Energy
• Binding energy• Reactions• Propulsion
Binding Energy
Some Fusion Reactions(1)
2 1D +
3 1T →
4 2He ( 3.5 MeV ) + n0 ( 14.1 MeV )
(2i) 2 1D +
2 1D →
3 1T ( 1.01 MeV ) + p+ ( 3.02 MeV )
50%
(2ii)
→ 3 2He ( 0.82 MeV ) + n0 ( 2.45 MeV )
50%
(3) 2 1D +
3 2He →
4 2He ( 3.6 MeV ) + p+ ( 14.7 MeV )
(4) 3 1T +
3 1T →
4 2He
+ 2 n0
+ 11.3 MeV
(5) 3 2He +
3 2He →
4 2He
+ 2 p+
+ 12.9 MeV
(6i) 3 2He +
3 1T →
4 2He
+ p+ + n0
+ 12.1 MeV
51%
(6ii)
→ 4 2He ( 4.8 MeV ) +
2 1D ( 9.5 MeV )
43%
(6iii)
→ 4 2He ( 0.5 MeV ) + n0 ( 1.9 MeV ) + p+ ( 11.9 MeV ) 6%
(7i) 2 1D +
6 3Li →
2 4 2He
+ 22.4 MeV
(7ii)
→ 3 2He +
4 2He
+ n0
+ 2.56 MeV
(7iii)
→ 7 3Li + p+
+ 5.0 MeV
(7iv)
→ 7 4Be + n0
+ 3.4 MeV
(8) p+ + 6 3Li →
4 2He ( 1.7 MeV ) +
3 2He ( 2.3 MeV )
(9) 3 2He +
6 3Li →
2 4 2He
+ p+
+ 16.9 MeV
(10) p+ + 11 5B →
3 4 2He
+ 8.7 MeV
http://en.wikipedia.org/wiki/Nuclear_fusion
Nuclear Reactions
• DT Fusion Reaction
• Uranium Fission
• Lithium Fission
10
42
31
21 nHeHH
10
23892
10 2
21
1nXXUn N
kN
k
31
42
63
10 HHeLin
Fusion Reactions
• The DT reaction
• And Lithium fission reaction
• Are equivalent to
10
42
31
21 nHeHH
31
42
63
10 HHeLin
42
42
63
2 HeHeLiH1
Reaction Cross-Section
Reaction Kinetics
• Rate -
• Parameter -
• Velocity depends on temperature
–
– k is Boltzmann’s constant
nv
v
kTmv2
3
2
1 2
Thermonuclear Weapon
Magnetic Confinement Fusion PowerTokamak
http://upload.wikimedia.org/wikipedia/commons/4/4b/Tokamak_fields_lg.png
Magnetic Confinement Fusion PowerMirror
http://www.google.com “magnetic mirror nuclear fusion reactor pictures”
Inertial Confinement Fusion Power
The stages of inertial confinement fusion:
1. Laser beams or laser-produced X-rays rapidly heat the surface of the fusion target, forming a surrounding plasma envelope.
2. Fuel is compressed by the rocket-like blowoff of the hot surface material. 3. During the final part of the capsule implosion, the fuel core reaches 20 times the density
of lead and ignites at 100,000,000 ˚C. 4. Thermonuclear burn spreads rapidly through the compressed fuel, yielding many times
the input energy.
The blue arrows represent radiation; orange is blowoff; purple is inwardly transported thermal energy.
http://en.wikipedia.org/wiki/File:Inertial_confinement_fusion.svg
Fusion Rockets
• Magnetic Mirror– End fields unequal: preferential exhaust
• Tokamak– Power to expel high speed plasma
• Inertial Confinement– Magnetic nozzles align pellet products
Orion
Daedalus StudyBritish Interplanetary Society
From Nicolson “The Road to the Stars”
Daedalus
http://www.grc.nasa.gov/WWW/PAO/images/warp/warp44.gif
Medusa
http://en.wikipedia.org/wiki/File:MedusaNuclearPropulsionOperatingSequenceDrawing.png
Medusa
Specific Impulse:100,000-500,000
http://en.wikipedia.org/wiki/File:MedusaNuclearPropulsionOperatingSequenceDrawing.png
Matter-Antimatter Annihilation
ee
Positron-Electron Annihilation
nnmpp 0
nnmpn )1(0
Antiproton-Uranium Nucleus Annihilation
+
p
p
n
knXUp 223892
Courtesy of G. Smith
Pellet Ignition
Tritium Fuel Considerations
• Tritium is naturally radioactive– Beta decay– Half-life ~12 years
• Tritium requires cryogenic storage• Lithium-6 is not radioactive• Lithium-6 does not require cryogenic storage
Pellet Construction
Hybrid Fusion-Fission Nuclear Pulse Propulsion
• Use of Li6 – Reduces tritium handling problems– Decreases specific impulse
• System can be developed in a two step process– Use fusion to boost the specific impulse of a pulse
fission rocket– Evolve to a full hybrid system
Typical PelletGeometry
• Core radius 0.05 mm• Fuel Radius 1.00 cm• Tungsten Shell Thickness 0.10 mm• Antiproton Beam Radius 0.10 m• Uranium Hemisphere Radius 0.30 mm
Typical Pellet Performance
• Antiproton Pulse 2x1013 for 30 ns• Maximum Field 24 MG• Pellet Mass 3.5 g• Specific Impulse
– 600,000 s for 100% fusion– 200,000 s for 10% fusion– 3,000 s for contained fusion
Exotic Propulsion Alternatives
Sanger Electron-PositronAnnihilation Rocket
By G. Matloff
Proton-Antiproton Reaction
nnmpp 0
Proton-Antiproton Reaction
nnmpp 0
Proton-Antiproton Reaction
nnmpp 0
Proton-Antiproton Reaction
nnmpp 0
ee
ee
Proton-Antiproton Reaction
nnmpp 0
ee
ee
+
Proton-Antiproton Reaction
nnmpp 0
ee
ee
+
Pion Rocket
By R. ForwardIsp: 10,000,000 sec
References• Kammash, T., (editor), Fusion Energy in Space Propulsion, Volume 167 Progress in
Astronautice and Aeronautics, American Institute of Aeronautics and Astronautics, Washington, DC,, 1995.
• Kammash, T, Fusion Reactor Physics, Ann Arbor Physics, Inc. Ann Arbor, MI, 1976.• Manheimer, W.M., An Introduction to Trapped-Particle Instability in Tokamaks,
Energy Research and Development Administration, Washington, DC, 1972.• Miley, G.K., Fusion Energy Conversion, American Nuclear Society and U.S. Energy
research and Development Administration, Chicago, 1976.• Miyamoto, K., Plasma Physics for Nuclear Fusion, The MIT Press, Cambridge, MA,
1987.• Vedenov, A.A., Theory of Turbulent Plasma, National Aeronautics and Space
Administration, National Science Foundation, and Isreal Program for Scientific Translations, Jerusalem, 1966.
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