arXiv subjects

A. E. Kaplan

Publications and source records attributed to A. E. Kaplan.

14 recordsLinked to original sources

arXiv2019

Coulomb cluster explosion boosted by an electrical pulse -- neutron source, diagnostic tool, and test of nuclear fusion efficiency

To greatly enhance output of fusion-produced neutrons in a laser-initiated Coulomb explosion of $D$ clusters, we propose to accelerate $D^+$ ions by an electrical pulse to the energies where the $D^+ + D$ collision cross-section is the highest. With $D^+$ ions bombarding a $D$-rich cathode, this solves a few problems simultaneously by (a) removing electron cloud hindering the Coulomb explosion, (b) utilizing up to $100 \%$ of the ions to hit the high-density packed nuclei, and (c) reaching highly increased cross-section of neutron production in a single $D^+ + D$ collision, by using a multi-layered target. We show that neutron output can reach up to $10^{15}$ per shot, which provides for a powerful and compact neutron source. We also consider the use of $E$-pulse acceleration for diagnostic purposes.

physics.atm-clus↗

arXiv2018

True wavefunctions and antiparticles of Klein-Gordon equation: $\hbar$-conjugation, elimination of $CPT$-invariance, and anti-gravitation

While revisiting Klein-Gordon relativistic quantum equation for spin-0 particles, we predicted that $\hbar$ reverses its sign for negative energies, and formulated a universal symmetry rule, whereby all the parameters that couple particles to external fields reverse their sign along with $\hbar$ at a particle$\leftrightarrow$antiparticle transformation; this in particular implies anti-gravitation between matter and antimatter. Our results suggest that the $\hbar$-conjugation principle and related invariance may replace $CPT$-invariance in general relativistic quantum mechanics.

physics.gen-ph↗

arXiv2018

Compton light pressure and spectral imprint of relic radiation on cosmic electrons

A fully QED/relativistic theory of light pressure of CMB radiation and Fokker-Planck equation for electron distribution combined with cosmologic relation for CMB temperature, T, yields analytic results for the evolution of the distribution over large span of time and energies. A strong imprint of CMB on electrons transpires via formation of "frozen non-equilibrium" state of electrons in current epoch, and possible existence of cutoff and narrow spectral lines as remnants of high-T sources.

astro-ph.CO↗

arXiv2018

Coulomb cluster explosion boosted by a quasi-dc pulse -- diagnostic tool and ultimate test of laser fusion efficiency in clusters

To greatly enhance output of nuclear fusion produced neutrons in a laser-initiated Coulomb explosion of Deuterium clusters, we propose to accelerate the resulting ions by a quasi-$dc$ electrical pulse to the energies where the $D^+ + D$ collision cross-section is the highest. With $D^+$ ions bombarding then a Deuterium-rich solid-state cathode, this allows one to solve a few problems simultaneously by (a) completely removing electron cloud hindering the Coulomb explosion of ionic core, (b) utilizing up to 100% of the cluster ions to collide with the high-density packed nuclei, and (c) reaching highly increased cross-section of neutron production in a single $D^+ + D$ collision, in particular by using a multi-layered target. We also consider the use of E-pulse acceleration for diagnostic purposes.

physics.atm-clus↗

arXiv2015

Fully QED/relativistic theory of light pressure on free electrons by isotropic radiation

A relativistic/QED theory of light pressure on electrons by an isotropic, in particular blackbody radiation predicts thermalization rates of free electrons over entire span of energies available in the lab and the nature. The calculations based on the QED Klein-Nishina theory of electron-photon scattering and relativistic Fokker-Planck equation, show that the transition from classical (Thompson) to QED (Compton) thermalization determined by the product of electron energy and radiation temperature, is reachable under conditions for controlled nuclear fusion, and predicts large acceleration of electron thermalization in the Compton domain and strong damping of plasma oscillations at the temperatures near plasma nuclear fusion.

quant-ph↗

arXiv2015

All-band Bragg solitons and cw eigenmodes

We found an amazingly simple general "all-band" intensity profile of bandgap (Bragg) solitons for arbitrary parameters of spatially-periodic nonlinear systems, similar to those of multi-frequency stimulated Raman scattering, in particular the so called Lorentzian-profile solitons. We also found nonlinear eigen-modes of such system that propagate without energy exchange between waves.

physics.optics↗

arXiv2012

Beyond Attoseconds

We briefly review the pilot ideas on the generation of EM-pulses much shorter than already available sub-femtosecond pulses, and outline inroads and venues into the physics of pulses mush shorter than an attosecond (10^-18 s), in particular the so called zeptosecond (10^-21 s) and yoctosecond (10^-24 s) pulses that may allow one to operate on QED and nuclear as well as quark-gluon time plasma scales. We also very briefly outline the entire time-scale available in the existing universe, down to the ultimately short the so called Planck time ~ 10^-43 s, which is the time-scale of Big Bang, and the most significant time-scale-posts on the road to it.

physics.optics↗

arXiv2010

Optical Multi-hysteresises and "Rogue Waves" in Nonlinear Plasma

An overdense plasma layer irradiated by an intense light can exhibit dramatic nonlinear-optical effects due to a relativistic mass-effect of free electrons: highly-multiple hysteresises of reflection and transition, and emergence of gigantic "rogue waves". Those are trapped quasi-soliton field spikes inside the layer, sustained by an incident radiation with a tiny fraction of their peak intensity once they have been excited by orders of magnitude larger pumping. The phenomenon persists even in the layers with "soft" boundaries, as well as in a semi-infinite plasma with low absorption.

physics.plasm-ph↗

arXiv2010

Local-field excitations in 2D lattices of resonant atoms

We study excitations of the local field (locsitons) in nanoscale two-dimensional (2D) lattices of strongly interacting resonant atoms and various unusual effects associated with them. Locsitons in low-dimensional systems and the resulting spatial strata and more complex patterns on a scale of just a few atoms were predicted by us earlier [A. E. Kaplan and S. N. Volkov, Phys. Rev. Lett., v. 101, 133902 (2008)]. These effects present a radical departure from the classical Lorentz-Lorenz theory of the local field (LF), which assumes that the LF is virtually uniform on this scale. We demonstrate that the strata and patterns in the 2D lattices may be described as an interference of plane-wave locsitons, build an analytic model for such unbounded locsitons, and derive and analyze dispersion relations for the locsitons in an equilateral triangular lattice. We draw useful analogies between one-dimensional and 2D locsitons, but also show that the 2D case enables locsitons with the most diverse and unusual properties. Using the nearest-neighbor approximation, we find the locsiton frequency band for different mutual orientations of the lattice and the incident field. We demonstrate a formation of distinct vector locsiton patterns consisting of multiple vortices in the LF distribution and suggest a way to design finite 2D lattices that exhibit such patterns at certain frequencies. We illustrate the role of lattice defects in supporting localized locsitons and also demonstrate the existence of "magic shapes", for which the LF suppression at the exact atomic resonance is cancelled.

physics.optics↗

arXiv2009

Single-particle motional oscillator powered by laser

An ion, atom, molecule or macro-particle in a trap can exhibit large motional oscillations due to the Doppler-affected radiation pressure by a laser, blue-detuned from an absorption line of a particle. This oscillator can be nearly thresholdless, but under certain conditions it may exhibit huge hysteretic excitation. Feasible applications include a "Foucault pendulum" in a trap, a rotation sensor, single atom spectroscopy, isotope separation, etc.

physics.atom-ph↗

arXiv2009

Nanostratification of optical excitation in self-interacting 1D arrays

The major assumption of the Lorentz-Lorenz theory about uniformity of local fields and atomic polarization in dense material does not hold in finite groups of atoms, as we reported earlier [A. E. Kaplan and S. N. Volkov, Phys. Rev. Lett., v. 101, 133902 (2008)]. The uniformity is broken at sub-wavelength scale, where the system may exhibit strong stratification of local field and dipole polarization, with the strata period being much shorter than the incident wavelength. In this paper, we further develop and advance that theory for the most fundamental case of one-dimensional arrays, and study nanoscale excitation of so called "locsitons" and their standing waves (strata) that result in size-related resonances and related large field enhancement in finite arrays of atoms. The locsitons may have a whole spectrum of spatial frequencies, ranging from long waves, to an extent reminiscent of ferromagnetic domains, -- to super-short waves, with neighboring atoms alternating their polarizations, which are reminiscent of antiferromagnetic spin patterns. Of great interest is the new kind of "hybrid" modes of excitation, greatly departing from any magnetic analogies. We also study differences between Ising-like near-neighbor approximation and the case where each atom interacts with all other atoms in the array. We find an infinite number of "exponential eigenmodes" in the lossless system in the latter case. At certain "magic" numbers of atoms in the array, the system may exhibit self-induced (but linear in the field) cancellation of resonant local-field suppression. We also studied nonlinear modes of locsitons and found optical bistability and hysteresis in an infinite array for the simplest modes.

physics.optics↗

arXiv2009

Laser Gate: Multi-MeV electron acceleration and zeptosecond e-bunching

Relativistically-intense laser beam with large field gradient ("laser gate") enables strong inelastic scattering of electrons crossing the beam. This process allows for multi-MeV electron net acceleration per pass within the wavelength space. Inelastic scattering even in low-gradient laser field may also induce extremely tight temporal focusing and electron bunch formation down to quantum, zepto-second limit.

physics.atom-ph↗

arXiv1998

Quantum Carpets made simple

We show that the concept of degeneracy is the key idea for understanding the quantum carpet woven by a particle in the box.

quant-ph↗

arXiv1998

The Particle in the box: Intermode traces in the propagator

Characteristic structures such as canals and ridges --intermode traces-- emerge in the spacetime representation of the probability distribution of a particle in a one-dimensional box. We show that the corresponding propagator already contains these structures. We relate their visibility to the factorization property of the initial wave packet.

quant-ph↗