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本解説では，粒子制御に向けたこれまでの取り組みとして，主として粒子排気という視点に立ち，プラズマ対向壁の燃料粒子吸蔵，放出現象のほか，ダイバータによる効率的な燃料排出について筆者が行ってきた研究を中心に紹介する．また，粒子制御を行うための重要な計測手法として，中性粒子圧力計測の一つである高速イオンゲージ開発の進展についても触れる．そのほか，燃焼プラズマで想定される水素同位体，ヘリウム混合プラズマ中の同位体分離や，効率的な粒子排出を可能にする粒子制御手法についても紹介し，これからの粒子制御に向けた展望を述べる．

The paper presents the results of theoretical study for the influence of an additional magnetostatic field applied to the radio-frequency discharge region on the operating parameters of radio-frequency ion injector, taking into account the shape of its discharge chamber. The integral characteristics are calculated for three injector configurations: with a cylindrical, conical, and hemispherical discharge chamber. For calculations, we used a mathematical model, in which the charged particle behavior in plasma is described by relations close to magnetohydrodynamic, while the neutral particle distribution is determined using an approximate analytical solution obtained when considering a one-dimensional problem of gas flow in a tube. Simulation was carried out in the COMSOL Multiphysics software package. According to the calculation results, an additional magnetostatic field can improve the ion injector performance with any discharge chamber configuration. The greatest operation efficiency increase was observed with a cylindrical discharge chamber. However, according to calculations, the best performance can be obtained if a hemispherical chamber is used.

Presented here is an application of the Response Matrix (RM†) method for adjoint discrete ordinates (SN) problems in slab-geometry applied to energy-dependent neutral particle transport problems. T...

Electret filters display enhanced ability for particle collection due to its additional electrostatic attraction. However, their efficiency degradation during particle loading remains to be solved. Herein, the loading characteristics of electret filters with neutral particles is investigated via immersed boundary-lattice Boltzmann method (IB-LBM). The specific charge distribution on the electret fibers, and the fiber charge decay due to gas neutralization and particle conduction are incorporated in the model. Results verify that the distribution of bipolar charges randomly on fibers with equivalent area is reasonable. The efficiency degradation depends on the proportion of electrostatic collection in the whole particle filtration process, and the attenuation of electrostatic intensity in the electret filter. With the same loaded mass, carbon particles with higher conductivity cause more charge decay and efficiency degradation than NaCl and Al2O3 particles. The fiber charge is mainly lost through conduction, and gas neutralization becomes important only for high-resistivity materials.

The process of atomic nucleus recoil under the elastic scattering of a neutral particle, a hypothetical dark matter particle (WIMP) in particular, is considered. In the case of a low-energy recoil of the nucleus, the relations between the probability of ionization of the recoil atom and the cross section of ionization of such an atom by a photon, as well as by an electron, are obtained. These expressions contain only one parameter, the values of which are calculated for different types of atoms, taking into account experimental data on ionization by photons and electrons. The probabilities of ionization of noble-gas recoil atoms are compared with the results of other theoretical studies, and it is emphasized that the proposed calculating model is quite reliable and its accuracy is determined by the error of the experimental cross sections that are used.

In this paper, the transient process of negative DC corona generated with needle to plane electrode covered by polymer film is investigated by numerical simulation considering air plasma chemistry. The variation in plasma species in corona discharge and the transient process of charge accumulation on the film are examined. Moreover, the electric field and the mean electron energy distribution on the sample surface are discussed. Obtained results indicate that during the corona process, O 2 +, O 4 + and N 4 + are the dominant positive ions, O 2 − and O are the main negative ion and the neutral particle, respectively. The charge accumulation region expands along the radial direction and the charge density increases gradually. In addition, the discharge channel shape is changed from column to cone with time, which is attributed to the electric field modification achieved by the accumulated charges. In 2000 ns, the mean electron energy distribution on the polymer surface varies between 2.1 and 5.8 eV and finally stabilizes to 3.7 eV, thus the electrons can overcome the barrier at gas-solid interface and become injected into the polymer bulk. It is suggested that the polymer surface charging transient is highly associated with the plasma behavior.

A generalization of the Response Matrix spectral nodal method is applied to fixed–source discrete ordinates (SN) radiative transfer and neutron transport problems in slab geometry. This method is e...

The equation of motion for a relativistic neutral particle that moves in a medium characterized by a friction proportional to the square of the velocity is analyzed. The relativistic trajectory is derived in a numerical way and in the form of a Taylor series. The astrophysical applications cover the trajectory of SN 1993J and the light curve of gamma ray bursts.

The plasmaphysical code is presented that makes it possible to simulate the energy distributions of atoms escaping from plasma of the toroidal facilities. The code includes calculations of the particle spatial distributions in the charge-exchange plasma target consisting of atoms and hydrogen-like impurity ions. The calculations of the charge-exchange target are performed in two ways: using the Monte Carlo method and solving the ionization balance equation in the coronal approximation. The code can be used to interpret the neutral particle analyzers (NPAs) data. In particular, with its help, the ion temperatures determined using the NPAs can be corrected. The code can be also used to estimate the atomic fluxes from plasma onto the first wall expected at the currently designed fusion facilities.

From backgrounds of the Lorentz symmetry breaking implemented by the tensor $\left (K_{F}\right )_{\mu \nu \alpha \beta }$ , we analyze the effects of the Lorentz symmetry violation at a low energy scenario from a semiclassical point of view by using the Wentzel, Kramers and Brillouin approximation. We show that the interaction of a neutral particle with electric and magnetic fields in the background defined by the tensor $\left (K_{F}\right )_{\mu \nu \alpha \beta }$ yields attractive scalar potentials, and thus, bound state solutions to the Schrodinger equation can be obtained.

By exploring the hypothesis of magnetic monopoles, we consider the existence of electric fields produced by magnetic current densities. Then, we consider a uniformly rotating frame with the purpose of searching for effects of rotation on the interaction of axial electric fields with the magnetic quadrupole moment of a neutral particle. Our analysis is made through the WKB (Wentzel, Kramers and Brillouin) approximation. Therefore, by applying the WKB approximation, we search for bound state solutions to the Schrodinger equation in two particular cases.

Core-ion temperature measurements are based on resolving the energy components and the analysis of fast neutrals coming out of the magnetic confinement of plasma. ADITYA-tokamak (R/a = 75 cm/25 cm) uses Neutral Particle Analyzer (NPA) based charge exchange diagnostic system for measurement of the core ion-temperature in the range of 100–300 eV of Aditya plasma. Several ohmic plasma discharges are investigated for the Aditya tokamak, which provides an estimate of core ion-temperature (Ti0) evaluation with time and its comparison with the core electron-temperature (Te0). The analysis shows the ratio of Ti0/Te0 is typically in the rage of 30%–40%. Attempts have been made to estimate the neutral hydrogen (nH°) density in the core regime and its evolution with time using a simple approach. The core neutral densities estimated in the order of 108–109 cm−3 for ohmic discharges in ADITYA-tokamak. Effect of the ion cyclotron radio frequency heating (ICRH) on the experimental charge-exchange spectrum is also observed, which shows a typical increase of the perpendicular ion temperature (Ti⊥) by ~ 50 eV.

—This article presents the results of an experiment on the processes of scattering of ions and neutral atoms on targets from polished tungsten obtained using a neutral particle facility. The neutral particle facility is a laboratory instrument designed to study the processes of reflection and scattering of charged particles and neutral atoms on the surfaces of targets made of various materials. The facility allows one to record the energy and angular distributions of secondary particles formed as a result of the interaction of a stream of ions of different energies or neutral atoms with a target installed at different angles.

The use of scintillators of micron thickness attached to the input windows of photomultiplier tubes (PMTs) makes it possible to create ion detectors with low sensitivity to neutrons and gamma rays. The manufacturing technology of such detectors based on the CsI(Tl) scintillator and Hamamatsu H8500D multianode PMT is described. The main steps of the process are considered, including vacuum thermal deposition of a scintillator onto substrates, gluing substrates to the PMT window, and quality control of the manufactured samples. The technology was developed for the manufacture of detectors for the neutral particle diagnostic system on the ITER tokamak reactor.

Due to the core assumptions of kinetic theory and the drive toward realizing reproducible gas-phase measurements, ion mobility experiments are commonly conducted in the presence of an inert, neat buffer gas, usually nitrogen or helium. Mixing drift gases in defined, static ratios can provide useful information not only for optimizing the separation of analytes but also for defining the interaction between the ion and neutral particle. In a foundational effort, we seek to validate the role of the drift gas polarizability on the observed mobility of the ions by systematically mixing drift gases to discretely access a range of bulk gas polarizabilities not given by pure drift gases. Compared to historical efforts to probe the role of polarizability on the ion-neutral collisional cross section where a linear relationship was assumed, the data collected in the present effort clearly illustrate a quadratic dependency of the ion-neutral particle collision cross section and polarizability (R2 > 0.999). When translating these data into the mobility dimension, we illustrate that the gas-phase mobility of polyatomic ions conforms to Blanc's law. These observations combined with considerations related to Langevin's polarization limit provide an experimental mechanism to estimate to what degree an ion-neutral interaction conforms to either the hard-sphere or induced-dipole model. To support these observations, additional comparisons are made with the respective reduced masses, polarizabilities, and mobilities of ions in mixtures where different degrees of hard-sphere interactions are present.

Magnetic energy release conversion, plasma heating and charged particle energization-acceleration in the magnetic fluctuation-induced self-generating-organization region and the plasma turbulence-induced self-feeding-sustaining region are key issues for large temporal-spatial scale turbulent magnetic reconnection (LTSTMR; observed current sheet thickness to characteristic electron length, electron Larmor radius for low-β and electron inertial length for high-β, ratios on the order of 1010∼1011; observed evolution time to electron cyclotron time ratios on the order of 1010∼1011) that ranges from Earth’s magnetosphere to solar eruptions and other astrophysical phenomena. As the first part of a two-paper series, this paper introduces a relativistic hybrid particle-in-cell and lattice Boltzmann (RHPIC-LBM) model that describes the continuous kinetic-dynamic-hydro fully coupled LTSTMR evolution process. First, based on the governing equations of resistive relativistic magnetohydrodynamics (MHD), the relativistic discrete distribution functions for a magnetic field (D3Q7), electric field (D3Q13), electromagnetic field (D3Q13), charged particle (D3Q19) and neutral particle (D3Q27) of different plasma species are obtained for the RHPIC-LBM lattice grid. Then, the numerical process, algorithm, pseudocode, flowchart and GPU-CPU heterogenous framework of the RHPIC-LBM are described. Finally, this model is tested and validated on Tianhe-2 from the National Supercomputer Center in Guang Zhou (NSCC-GZ) with 10,000 ∼ 100,000 CPU cores and 50∼120 hours per case. We investigate the solar atmosphere LTSTMR activities, including the picoscale ( 10 − 2 m ∼ 10 5 m), nanoscale ( 10 5 m ∼ 10 6 m), microscale ( 10 6 m ∼ 10 7 m), macroscale ( 10 7 m ∼ 10 8 m) and large hydroscale ( 10 8 m ∼ 10 9 m). All the simulation results are consistent with observations and theories. The validated model is applied to explore the turbulence evolution of the interactions of the magnetic helical structures in the 3D LTSTMR self-generating-organization magnetic field region and self-feeding-sustaining plasma region in Part II.

The geometric phase can be used as a fruitful venue of investigation to infer features of the quantum systems. Its application can reach new theoretical frontiers and imply innovative and challenging experimental proposals. Herein, we take advantage of the geometric phase to sense the corrections induced while a neutral particle travels at constant velocity in front of an imperfect sheet in quantum vacuum. As it is already known, two bodies in relative motion at constant velocity experience a quantum contactless dissipative force, known as quantum friction. This force has eluded experimental detection so far due to its small magnitude and short range. However, we give details of an innovative experiment designed to track traces of the quantum friction by measuring the velocity dependence of corrections to the geometric phase. We notice that the environmentally induced corrections can be decomposed in different contributions: corrections induced by the presence of the dielectric sheet and the motion of the particle in quantum vacuum. As the geometric phase accumulates over time, its correction becomes relevant at a relative short timescale, while the system still preserves purity. The experimentally viable scheme presented would be the first one in tracking traces of quantum friction through the study of decoherence effects on a NV center in diamond., version published in npj quantum informtion 2020

The Pierre Auger Observatory, which is the largest air-shower experiment in the world, offers unprecedented exposure to neutral particles at the highest energies. Since the start of data collection more than 18 years ago, various searches for ultra-high-energy (UHE, E & 1017 eV) photons have been performed, either for a diffuse flux of UHE photons, for point sources of UHE photons or for UHE photons associated with transient events such as gravitational wave events. In the present paper, we summarize these searches and review the current results obtained using the wealth of data collected by the Pierre Auger Observatory., Argentina-Comision Nacional de Energia Atomica, ANPCyT, Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Gobierno de la Provincia de Mendoza, Municipalidad de Malargue, NDM Holdings, Valle Las Lenas, Australian Research Council, Belgium-Fonds de la Recherche Scientifique (FNRS), FWO, Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ) Fundacao de Apoio a Pesquisa do Distrito Federal (FAPDF) Financiadora de Inovacao e Pesquisa (Finep) Fundacao Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio De Janeiro (FAPERJ) Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) 2019/10151-2 2010/07359-6 1999/05404-3, Ministerio da Ciencia, Tecnologia, Inovacoes e Comunicacoes (MCTIC), France-Centre de Calcul IN2P3/CNRS Centre National de la Recherche Scientifique (CNRS) Region Ile-de-France Centre National de la Recherche Scientifique (CNRS) Departement Sciences de l'Univers (SDU-INSU/CNRS) French National Research Agency (ANR) LABEX ANR-10-LABX-63 ANR-11-IDEX-0004-02, Federal Ministry of Education & Research (BMBF) German Research Foundation (DFG) Finanzministerium Baden-Wurttemberg Helmholtz Alliance for Astroparticle Physics (HAP) Helmholtz Association Ministerium fur Kultur und Wissenschaft des Landes Nordrhein-Westfalen Ministerium fur Wissenschaft, Forschung und Kunst des Landes Baden-Wurttemberg, Italy-Istituto Nazionale di Fisica Nucleare (INFN) Istituto Nazionale Astrofisica (INAF), Ministry of Education, Universities and Research (MIUR), CETEMPS Center of Excellence, Ministry of Foreign Affairs and International Cooperation (Italy), Consejo Nacional de Ciencia y Tecnologia (CONACyT) 167733 Universidad Nacional Autonoma de Mexico Programa de Apoyo a Proyectos de Investigacion e Innovacion Tecnologica (PAPIIT) Universidad Nacional Autonoma de Mexico, Netherlands-Ministry of Education, Culture and Science Netherlands Organization for Scientific Research (NWO), SURF Cooperative, Poland-Ministry of Education and Science DIR/WK/2018/11 National Science Centre, Poland 2016/22/M/ST9/00198 2016/23/B/ST9/01635 2020/39/B/ST9/01398, Portuguese Foundation for Science and Technology FEDER funds within Programa Operacional Factores de Competitividade through FundacAo para a Ciencia e a Tecnologia (COMPETE), Romania-Ministry of Research, Innovation and Digitization, CNCS/CCCDI UEFISCDI within the National Nucleus Program PN19150201/16N/2019 PN1906010 PNCDI III TE128 PN-III-P1-1.1-TE-2021-0924/TE57/2022 PED289, Slovenian Research Agency - Slovenia P1-0031 P1-0385 I0-0033 N1-0111, Spanish Government FPA2017-85114-P PID2019-104676GB-C32, Xunta de Galicia, European Commission ED431C 2017/07, Junta de Andalucia SOMM17/6104/UGR P18-FR-4314, European Commission, RENATA Red Nacional Tematica de Astroparticulas FPA2015-68783-REDT, Maria de Maeztu Unit of Excellence MDM-2016-0692, United States Department of Energy (DOE) DE-AC02-07CH11359 DE-FR02-04ER41300 DE-FG02-99ER41107 DE-SC0011689, National Science Foundation (NSF) 0450696, Grainger Foundation, Marie Curie-IRSES/EPLANET, European Particle Physics Latin American Network, UNESCO, MSMT CR LTT18004 LM2015038 LM2018102 CZ.02.1.01/0.0/0.0/16_013/0001402 CZ.02.1.01/0.0/0.0/18_046/0016010 CZ.02.1.01/0.0/0.0/17_049/0008422