Bulletin of the American Physical Society
58th Annual Meeting of the APS Division of Plasma Physics
Volume 61, Number 18
Monday–Friday, October 31–November 4 2016; San Jose, California
Session YO7: Chaos, Cross Sections, Mega Gauss Fields |
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Chair: Mark Koepke, West Virginia University Room: 212 AB |
Friday, November 4, 2016 9:30AM - 9:42AM |
YO7.00001: Chaotic orbit effects in a stationary single particle probabilistic density Shun Ogawa, Xavier Leoncini, Michel Vittot, Guilhem Dif-Pradalier, Xavier Garbet Chaotic particle orbit effects in a stationary density function or macroscopic quantities are investigated. A considered field consists with static magnetic field and null electric field in a cylinder, then a test particle is driven by the Lorentz force. We firstly consider an axisymmetric magnetic field, where three integrals of motion coexist. So that the test particle motion is completely integrable, and its Hamiltonian is reduced to an effective one degree of freedom Hamiltonian. For some initial states, the effective potential of this reduced Hamiltonian has a saddle point and a separatrix bringing about some chaos when a perturbation is added to the magnetic field. We investigate how this chaos modifies the stationary density function. [Preview Abstract] |
Friday, November 4, 2016 9:42AM - 9:54AM |
YO7.00002: Effect of giant charge-transfer resonance $\sigma_{CT}\sim {10}^{9}$ barn on operation of magnetic fusion reactor below ``critical energy.'' Timothy Hester, Bogdan Maglich, Dan Scott, Alexander Vaucher Charge transfer (CT) reactivity was assumed to be negligible compared to ionization (IO) before Belfast measurements$^{1-3}$ revealed the opposite: CT predominance over IO, $\sigma_{CT}\approx {10}^{9}\mathrm{b,}\sigma _{CT} \mathord{\left/ {\vphantom {\sigma_{CT} \sigma_{IO}}} \right. \kern-\nulldelimiterspace} \sigma_{IO}\approx U\approx 100$, below critical `atomic unit of velocity', $v_{o}=2.2\times {10}^{8}{cms}^{-1}$, which is orbital velocity of e in H atom. Near v$_{o}$, $U=1$, i.e. $\sigma_{CT}\sim \sigma_{IO}$. Critical ion energy is $T_{0}\left( \mathrm{lab} \right)=k\, 25\, M\, \left[ \mathrm{KeV} \right]=200\, \mathrm{KeV\, for}\, [ERR:md:MbegChr=0x2329,MendChr=0x232A,nParams=1] =\mathrm{ion\, mass\, }\left[ \mathrm{amu} \right]=4\, \mathrm{for\, DT\, mix};k=2$. ``Burnout'' pumping that requires $U\ll 1$ is inoperable in the $U\gg 1$ regime whereas CT continually acts like compressor increasing operating vacuum pressure during neutral beam discharge to 10$^{-3}$ Torr/0.3 s; this, in turn, sets upper limits to ion life-time against neutralization to $\bar{\tau }={10}^{-6}$ s. $\bar{\tau }$ is ${10}^{5}$ times shorter than thermalization time constant; hence plasma cannot be created. Lawson$^{4}$ was unaware of CT resonance; his ``critical temperature'' (30 KeV for DT) should be replaced with $T_{0}$. 1. Gilbody, Physica Scripta 23, 143 (1981); 2. Gilbody, AIP 360.19 (1996); 3. Post, Pyle, Atomic Molec. Phys. Contr. Fusion p. 477, Jochain (Ed.) Plenum Press(1983); 4. Lawson, Proc. Phys. Soc. B70, 6 (1957). [Preview Abstract] |
Friday, November 4, 2016 9:54AM - 10:06AM |
YO7.00003: Classical physics impossibility of magnetic fusion reactor with neutral beam injection at thermonuclear energies below 200 KeV. Bogdan Maglich, Timothy Hester, Alexander Vaucher Lawson criterion was specifically derived for inertial fusion and DT gas of stable lifetime without ions and magnetic fields$^{1}$. It was revised with realistic parametrers$^{2}$. To account for the losses of unstable ions against neutralization with lifetime $\tau $, $n\left( t \right)=n\tau \left[ 1-exp\left( \raise0.7ex\hbox{${-t}$} \!\mathord{\left/ {\vphantom {{-t} \tau }}\right.\kern-\nulldelimiterspace}\!\lower0.7ex\hbox{$\tau $} \right) \right]\to n\tau \, \mathrm{for}\, \tau \ll t$, where $\tau ^{-1}=n_{0}[ERR:md:MbegChr=0x2329,MendChr=0x232A,nParams=1] $, $n_{0}=\, $residual gas density. Second revised criterion becomes: $ntL={10}^{14}{\mathrm{cm}}^{\mathrm{-3}}\mathrm{s},\, tL=$ Lawson conf. time becomes $n\tau tL={10}^{14}\, \mathrm{or}\, ntL={10}^{16}/\tau $. In CT resonance regime below critical energy To, $\tau \sim {10}^{-5}$, and Lawson requirement $nt_{L}\sim {10}^{21}$ i.e. not realistic. Luminosity (reaction rate for $\sigma =1)$ is that of two unstable particles each with lifetime $\tau $: $L=n^{2}\left( t \right)v_{12}=n^{2}t^{2}v_{12}$. In subcritical regime, $L={10}^{-10}n^{2}\, \mathrm{for}\, n={10}^{14}{\mathrm{cm}}^{\mathrm{-3}},\, v\sim {10}^{9}\mathrm{cm\, }\mathrm{s}^{\mathrm{-1}}=L={10}^{27}$. . Which is negligible and implies a negative power flow reactor. But above $T_{0},\, \mathrm{at}\, T_{D}=725\mathrm{\, KeV},\, \tau =20s$ was observed implying $L={10}^{39}$ i.e. massive fusion energy production$^{3,4}$. 1. Lawson, Proc. Phys. Soc. B70, 6 (1957) 2. Maglich Miller, J. App. Phys. 46, 2916 [Fig. 13] (1975); 3. Phys. rev lett.54, 769 (1985); 4. NIM A271 pp. 1-128 (34 papers) [Preview Abstract] |
Friday, November 4, 2016 10:06AM - 10:18AM |
YO7.00004: The sharp-front magnetic diffusion wave of a strong magnetic field diffusing into a solid metal Bo Xiao, Zhuo-wei Gu, Ming-xian Kan, Gang-hua Wang, Jian-heng Zhao When a mega-gauss magnetic field diffuses into a solid metal, the Joule heat would rise rapidly the temperature of the metal, and the rise of temperature leads to an increase of the metal’s resistance, which in turn accelerates the magnetic field diffusion. Those positive feedbacks acting iteratively would lead to an interesting sharp-front magnetic diffusion wave. By assuming that the metal’s resistance has an abrupt change from a small value $\eta_{\rm S}$ to larger value $\eta_{\rm L}$ at some critical temperature $T_{\rm c}$, the sharp-front magnetic diffusion wave can be solved analytically. The conditions for the emerging of the sharp-front magnetic diffusion wave are $B_0>B_{\rm c}$, $\eta_{\rm L}/\eta_{\rm S} \gg 1$, and $\frac{\eta_{\rm L}}{\eta_ {\rm S}}\frac{B_0-B_{\rm c}}{B_{\rm c}} \gg 1$, where $B_{\rm c} = \sqrt{2\mu_0 J_{\rm c}}$, $B_0$ is the vacuum magnetic field strength, and $J_{\rm c}$ is the critical Joule heat density. The wave-front velocity of the diffusion wave is $V_{\rm c} = \frac{\eta_{\rm L}}{\mu_0}\frac{B_0-B_{\rm c}}{B_{\rm c}}\frac{1}{x_{\rm c}}$, where $x_{\rm c}$ is the depth the wave have propagated in the metal. In this presentation we would like to discuss the derivation of the formulas and its impact to magnetically driven experiments. [Preview Abstract] |
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