Resonant pair production in strong electric fields

1989 ◽  
Vol 39 (1) ◽  
pp. 334-339 ◽  
Author(s):  
John M. Cornwall ◽  
George Tiktopoulos
Keyword(s):  
Pair Production ◽  
Electric Fields ◽  
Strong Electric Fields

scholarly journals Dynamics of positrons during relativistic electron runaway

2018 ◽  
Vol 84 (5) ◽  
Author(s):  
O. Embréus ◽  
L. Hesslow ◽  
M. Hoppe ◽  
G. Papp ◽  
K. Richards ◽  
...  
Keyword(s):  
Pair Production ◽  
Electric Fields ◽  
Numerical Solutions ◽  
Production Cross ◽  
Analytical Formula ◽  
Rate Equations ◽  
Annihilation Radiation ◽  
Operational Parameters ◽  
Pair Production Cross Section ◽  
Strong Electric Fields

Sufficiently strong electric fields in plasmas can accelerate charged particles to relativistic energies. In this paper we describe the dynamics of positrons accelerated in such electric fields, and calculate the fraction of created positrons that become runaway accelerated, along with the amount of radiation that they emit. We derive an analytical formula that shows the relative importance of the different positron production processes, and show that, above a certain threshold electric field, the pair production by photons is lower than that by collisions. We furthermore present analytical and numerical solutions to the positron kinetic equation; these are applied to calculate the fraction of positrons that become accelerated or thermalized, which enters into rate equations that describe the evolution of the density of the slow and fast positron populations. Finally, to indicate operational parameters required for positron detection during runaway in tokamak discharges, we give expressions for the parameter dependencies of detected annihilation radiation compared to bremsstrahlung detected at an angle perpendicular to the direction of runaway acceleration. Using the full leading-order pair-production cross-section, we demonstrate that previous related work has overestimated the collisional pair production by at least a factor of four.

scholarly journals PAIR PRODUCTION DENSITY IN STRONG QED

2011 ◽  
Vol 01 ◽  
pp. 303-310 ◽  
Author(s):  
SANG PYO KIM ◽  
HYUN KYU LEE ◽  
YONGSUNG YOON
Keyword(s):  
Magnetic Fields ◽  
Pair Production ◽  
Electric Fields ◽  
Current Status ◽  
Strong Magnetic Fields ◽  
Strong Electric Fields

The current status of the research on pair production in strong QED is briefly reviewed not only for strong electric fields but also for strong magnetic fields in magnetically dominated astrophysical environment. A particular attention is paid to the spectral production number in the in- and out-state formalism and a possible prescription of the momentum integration is proposed to obtain the production density.

Calculation of the probability of optical transitions in strong electric fields

2000 ◽  
Vol 91 (5) ◽  
pp. 945-951 ◽  
Author(s):  
S. V. Bulyarskii ◽  
N. S. Grushko ◽  
A. V. Zhukov
Keyword(s):  
Electric Fields ◽  
Optical Transitions ◽  
Strong Electric Fields

Electrohydrodynamic rotation of drops at large electric Reynolds numbers

2016 ◽  
Vol 788 ◽  
Author(s):  
Ehud Yariv ◽  
Itzchak Frankel
Keyword(s):  
Electric Fields ◽  
Numerical Solutions ◽  
Fluid Velocity ◽  
Reynolds Numbers ◽  
Mirror Image ◽  
Liquid Drops ◽  
Weakly Conducting ◽  
Strong Electric Fields ◽  
Quincke Rotation ◽  
Asymmetric Solution

When subject to sufficiently strong electric fields, particles and drops suspended in a weakly conducting liquid exhibit spontaneous rotary motion. This so-called Quincke rotation is a fascinating example of nonlinear symmetry-breaking phenomena. To illuminate the rotation of liquid drops we here analyse the asymptotic limit of large electric Reynolds numbers, $\mathit{Re}\gg 1$, within the framework of a two-dimensional Taylor–Melcher electrohydrodynamic model. A non-trivial dominant balance in this singular limit results in both the fluid velocity and surface-charge density scaling as $\mathit{Re}^{-1/2}$. The flow is governed by a self-contained nonlinear boundary-value problem that does not admit a continuous fore–aft symmetric solution, thus necessitating drop rotation. Furthermore, thermodynamic arguments reveal that a fore–aft asymmetric solution exists only when charge relaxation within the suspending liquid is faster than that in the drop. The flow problem possesses both mirror-image (with respect to the direction of the external field) and flow-reversal symmetries; it is transformed into a universal one, independent of the ratios of electric conductivities and dielectric permittivities in the respective drop phase and suspending liquid phase. The rescaled angular velocity is found to depend weakly upon the viscosity ratio. The corresponding numerical solutions of the exact equations indeed collapse at large $\mathit{Re}$ upon the asymptotically calculated universal solution.

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