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The conventional approach for thermal quench mitigation in a tokamak disruption is through a high-Z impurity injection that radiates away the plasma's thermal energy before it reaches the wall. The downside is a robust Ohmic-to-runaway…

Plasma Physics · Physics 2025-10-15 Jason Hamilton , Luis Chacon , Giannis Keramidas , Xianzhu Tang

A method of slowing, accelerating, cooling, and bunching molecules and neutral atoms using time-varying electric field gradients is demonstrated with cesium atoms in a fountain. The effects are measured and found to be in agreement with…

Atomic Physics · Physics 2009-10-31 Jason A. Maddi , Timothy P. Dinneen , Harvey Gould

We use a probabilistic method to compute the propagation of an ionization front corresponding to the re-ionization of the intergalactic medium in a LCDM cosmology, including both hydrogen and helium. The effects of radiative transfer…

Astrophysics · Physics 2009-11-10 James Bolton , Avery Meiksin , Martin White

We discuss the non-radiative heat transfer in non-equilibrium double layer graphene system. We show that at the neutrality point the heat exchange is dominated by the inter-layer plasmon modes and derive analytic expressions for the heat…

Mesoscale and Nanoscale Physics · Physics 2020-11-25 Xuzhe Ying , Alex Kamenev

A near-minimal instance of optical cooling is experimentally presented wherein the internal-state entropy of a single atom is reduced more than twofold by illuminating it with broadband, incoherent light. Since the rate of optical pumping…

Quantum Physics · Physics 2024-11-08 Amanda Younes , Randall Putnam , Paul Hamilton , Wesley C. Campbell

Shocks are often invoked as heating mechanisms in astrophysical systems, with both adiabatic compression and dissipative heating that leading to temperature increases. Whilst shocks are reasonably well understood for ideal…

Solar and Stellar Astrophysics · Physics 2024-01-03 Ben Snow

We propose a new method to cool gaseous samples of neutral atoms. The gas is confined in a non dissipative optical trap in the presence of an homogeneous magnetic field. The method accumulates atoms in the $m_F=0$ Zeeman sub-level. Cooling…

Statistical Mechanics · Physics 2009-10-31 Gabriele Ferrari

Ion beam charge neutralization by electron injection is a complex kinetic process. Recent experiments show that resulting self-potential of the beam after neutralization by plasma could be much lower than the temperature of plasma electrons…

Plasma Physics · Physics 2020-05-20 Chaohui Lan , Igor D. Kaganovich

Negative triangularity tokamak plasmas feature naturally enhanced confinement in the so-called L-mode regime, irrespective of the power of external heating. This is in contrast to conventional scenarios, which require exceeding a given…

Plasma Physics · Physics 2025-10-24 Alessandro Balestri , Justin Ball , Stefano Coda

Energizing background ions plays a pivotal role in all forms of thermal nuclear fusion, as it can increase the fusion reaction rate without affecting the overall mechanical equilibrium. This is particularly critical for p11B fusion due to…

In moderately-coupled plasmas, a significant fraction of the internal energy resides in electric fields. As these plasmas are heated or compressed, the shifting partition of energy between particles and fields leads to surprising effects,…

Plasma Physics · Physics 2023-07-24 H. Fetsch , T. E. Foster , N. J. Fisch

We theoretically analyze the cooling dynamics of an atom which is tightly trapped inside a high-finesse optical resonator. Cooling is achieved by suitably tailored scattering processes, in which the atomic dipole transition either scatters…

Quantum Physics · Physics 2012-11-08 Marc Bienert , Giovanna Morigi

The intergalactic medium is expected to be at its coldest point before the formation of the first stars in the universe. Motivated by recent results from the EDGES experiment, we revisit the standard calculation of the kinetic temperature…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-21 Tejaswi Venumadhav , Liang Dai , Alexander Kaurov , Matias Zaldarriaga

Atoms in spatially dependent light fields are attracted to local intensity maxima or minima depending on the sign of the frequency difference between the light and the atomic resonance. For light fields confined in open high-Q optical…

Quantum Physics · Physics 2019-08-05 Arthur Jungkind , Wolfgang Niedenzu , Helmut Ritsch

We simulate ion loss induced by neutral beam injection (NBI) in three-dimensional (3D) space with high fidelity on the plasma-facing components (PFCs) of the Korea Superconducting Tokamak Advanced Research (KSTAR) device. Utilizing a 3D…

Plasma Physics · Physics 2025-03-17 Taeuk Moon , Tongnyeol Rhee , Jae-Min Kwon , Young-Mu Jeon , Eisung Yoon

The motion of neutral, polarizable atoms (also called neutral particles in this work) in the field of the Bessel beam is considered. It is shown in the numerical way, that the Bessel rings, i.e., the regions of high energy concentration can…

Optics · Physics 2019-12-18 Tomasz Radozycki

A recent survey of the fine-structure excitation of neutral carbon reveals that the interstellar medium in the Galactic plane exhibits a thermal pressure, nT/k, that ranges from about 10^3 to 10^4 cm{-3}K from one location to the next, with…

Astrophysics · Physics 2008-11-26 Edward B. Jenkins

Photoionizing radiation and stellar winds from massive stars deposit energy and momentum into the interstellar medium (ISM). They might disperse the local ISM, change its turbulent multi-phase structure, and even regulate star formation.…

Astrophysics of Galaxies · Physics 2018-06-06 Sebastian Haid , Stefanie Walch , Daniel Seifried , Richard Wünsch , František Dinnbier , Thorsten Naab

The growth and saturation of Buneman-type instabilities is examined with a particle-in-cell (PIC) simulation for parameters that are representative for the foreshock region of fast supernova remnant (SNR) shocks. A dense ion beam and the…

Solar and Stellar Astrophysics · Physics 2015-06-05 M. E. Dieckmann , A. Bret , G. Sarri , E. Perez Alvaro , I. Kourakis , M. Borghesi

A novel room-temperature ion source for the production of atomic ions in electron beam within wide ranges of electron energy and current density is developed. The device can operate both as conventional Electron Beam Ion Source/Trap…

Plasma Physics · Physics 2017-04-05 V. P. Ovsyannikov , A. V. Nefiodov , A. A. Levin