scholarly journals Modeling of inelastic collisions in a multifluid plasma: Ionization and recombination

2016 ◽  
Vol 23 (6) ◽  
pp. 063505 ◽  
Author(s):  
Hai P. Le ◽  
Jean-Luc Cambier
Author(s):  
Kun Ting Eddie Chua ◽  
Karia Dibert ◽  
Mark Vogelsberger ◽  
Jesús Zavala

Abstract We study the effects of inelastic dark matter self-interactions on the internal structure of a simulated Milky Way (MW)-size halo. Self-interacting dark matter (SIDM) is an alternative to collisionless cold dark matter (CDM) which offers a unique solution to the problems encountered with CDM on sub-galactic scales. Although previous SIDM simulations have mainly considered elastic collisions, theoretical considerations motivate the existence of multi-state dark matter where transitions from the excited to the ground state are exothermic. In this work, we consider a self-interacting, two-state dark matter model with inelastic collisions, implemented in the Arepo code. We find that energy injection from inelastic self-interactions reduces the central density of the MW halo in a shorter timescale relative to the elastic scale, resulting in a larger core size. Inelastic collisions also isotropize the orbits, resulting in an overall lower velocity anisotropy for the inelastic MW halo. In the inner halo, the inelastic SIDM case (minor-to-major axis ratio s ≡ c/a ≈ 0.65) is more spherical than the CDM (s ≈ 0.4), but less spherical than the elastic SIDM case (s ≈ 0.75). The speed distribution f(v) of dark matter particles at the location of the Sun in the inelastic SIDM model shows a significant departure from the CDM model, with f(v) falling more steeply at high speeds. In addition, the velocity kicks imparted during inelastic collisions produce unbound high-speed particles with velocities up to 500 km s−1 throughout the halo. This implies that inelastic SIDM can potentially leave distinct signatures in direct detection experiments, relative to elastic SIDM and CDM.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Andreas Kiontke ◽  
Mehrzad Roudini ◽  
Susan Billig ◽  
Amarghan Fakhfouri ◽  
Andreas Winkler ◽  
...  

AbstractMass spectrometry coupled to low-temperature plasma ionization (LTPI) allows for immediate and easy analysis of compounds from the surface of a sample at ambient conditions. The efficiency of this process, however, strongly depends on the successful desorption of the analyte from the surface to the gas phase. Whilst conventional sample heating can improve analyte desorption, heating is not desirable with respect to the stability of thermally labile analytes. In this study using aromatic amines as model compounds, we demonstrate that (1) surface acoustic wave nebulization (SAWN) can significantly improve compound desorption for LTPI without heating the sample. Furthermore, (2) SAWN-assisted LTPI shows a response enhancement up to a factor of 8 for polar compounds such as aminophenols and phenylenediamines suggesting a paradigm shift in the ionization mechanism. Additional assets of the new technique demonstrated here are (3) a reduced analyte selectivity (the interquartile range of the response decreased by a factor of 7)—a significant benefit in non-targeted analysis of complex samples—and (4) the possibility for automated online monitoring using an autosampler. Finally, (5) the small size of the microfluidic SAWN-chip enables the implementation of the method into miniaturized, mobile LTPI probes.


Author(s):  
Wen Xu ◽  
Zeyue Shen ◽  
Junliang Zhang ◽  
Tengyu Zhang ◽  
Huanming Wu ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Andreas Kiontke ◽  
Mehrzad Roudini ◽  
Susan Billig ◽  
Armaghan Fakhfouri ◽  
Andreas Winkler ◽  
...  

An amendment to this paper has been published and can be accessed via a link at the top of the paper.


2020 ◽  
Vol 2 (3) ◽  
Author(s):  
Elliot Bentine ◽  
Adam J. Barker ◽  
Kathrin Luksch ◽  
Shinichi Sunami ◽  
Tiffany L. Harte ◽  
...  

Author(s):  
Gaurang Ruhela ◽  
Anirvan DasGupta

We consider the problem of a hopping ball excited by a travelling harmonic wave on an elastic surface. The ball, considered as a particle, is assumed to interact with the surface through inelastic collisions. The surface motion due to the wave induces a horizontal drift in the ball. The problem is treated analytically under certain approximations. The phase space of the hopping motion is captured by constructing a phase-velocity return map. The fixed points of the return map and its compositions represent periodic hopping solutions. The linear stability of the obtained periodic solution is studied in detail. The minimum frequency for the onset of periodic hops, and the subsequent loss of stability at the bifurcation frequency, have been determined analytically. Interestingly, for small values of wave amplitude, the analytical solutions reveal striking similarities with the results of the classical bouncing ball problem.


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