Page 1 - An Interesting Poster to look at from the Tri Alpha Energy Team in California

Fusion Enhancement from Bunched Ion Beams
B. Scott Nicks, A. Necas, T. Tajima, and the TAE Team
TAE Technologies, Inc., 19631 Pauling, Foothill Ranch, CA 92610
1. Motivation
 Experiments1 indicate non-destructive ion cyclotron mode in C-2U, likely in scrape-off-layer (SOL) of FRC
 Anomalous neutron rate observed, exceeding predicted thermonuclear value by > 102
 Beam-driven ion-Bernstein mode seen theoretically, exhibits wakefield character that creates similar large fast ion tail and fusion enhancement
 If beams are seeded with density modulations at the wavelength of the dominant mode, fusion enhancement is further improved
3. Beam-Driven Ion-Bernstein Wakefield
4. Beam-Driven Ion-Bernstein Wakefield
Ion Phase Space and Wakefield
Reactivity Scaling with Beam Velocity
 Beam-driven ion-Bernstein modes at beam cyclotron harmonics along Alfven speed, shifted by beam resonance condition: 𝜔 = 𝑘∥𝑣𝑏∥ + 𝑛Ω𝑏
 Manifests as wakefield, saturation at Tajima-
11 10
10 10
109 108 107
Fusion Rate2
≈ 300
Dawson field:
𝑚 𝜔𝑣 𝑣
𝐸 = 𝑖 𝜙=𝑛𝐵 𝐴 𝑇𝐷 𝑞𝑖 0𝑐
 Wake peaks accelerate ions to phase velocity, execute cyclotron motion
 Large increase in D-D reactivity: > 𝟏𝟎𝟒 over thermonuclear
 Creates beam/ion density fluctuations
−2 0 2 4 6 8 𝑡 (ms)
2. Scan of Ion-Cyclotron Modes
 Implicit PIC code LSP (1-2/2D)3
 Uniform 𝐵0 ∥ 𝑧Ƹ, SOL background (electrons, deuterium)
 Propagation angle 𝜃𝑘, beam injection angle 𝜃𝑏, relative to 𝐵0.  𝜽𝒌 = 𝟖𝟓∘, 𝜽𝒃 = 𝟕𝟓∘ best for fusion enhancement
𝒛ො
𝒚ෝ
𝑣Ԧ𝑏
𝜃𝑘
 Boron-11 plasma rather than deuterium
 Reduction in Alfven speed  proportional reduction in saturation
 Boosting of ion plasma frequency creates preference for continuum mode
 Low-frequency component adds secondary length scale
Ion Phase Space and Wakefield (B11)
5. Beam-Driven Boron-11 Wakefield
1.E+09
1.E+06
1.E+03
1.E+00
4 8 16 32 64 128
No bunching
Beam density modulation (Bunching)
𝝀𝒃 = 𝟐𝝅𝒗𝑨Τ𝒏𝛀𝒊
v Τ/ v 𝒗𝒗
2𝑛𝑏0 0
b𝒃 𝑻th𝒊i
n𝑛2=bu2nbcuhnincgh n𝑛1=bu1nbcuhnincgh C-2U
Density Fluctuations and Wakefield
𝑥/𝜆, 𝜆 = 2𝜋𝑣 /2Ω 𝐴𝑖
 Bunching at wavelength of dominant mode
 Scan over beam energies with bunching
𝟓.𝟔
𝜆=2𝜋𝑣 ΤΩ and𝜆=2𝜋𝑣 Τ2Ω andnobunching
𝐴𝑖𝐴𝑖
 Fusion enhancement scaling: 𝑭 ∝ 𝒗𝒃Τ𝒗𝑻𝒊
 For 𝑣𝑏Τ𝑣𝑇𝑖 < 32, enhancement improved
 For 𝑣𝑏Τ𝑣𝑇𝑖 > 32, bunching converges to non- bunched case, and dispersion relation moves
away from IB modes
 C-2U result broadly falls along power law
≈ 4𝜆
References
1. R. Magee, “Collective Phenomena in the Advanced, Beam- Driven FRC”, IAEA, 2017
2. R. M. Magee, TAE
3. D. R. Welch, D. V. Rose, B. V. Oliver, and R. E.
𝒌 ∥ 𝒙ෝ
Clark, Nucl. Inst. Meth. Phys. Res. A 464, 134 (2001).
Rate (s-1)
Fusion Enhancement