相关论文: Ionization rates in the heliosheath and in astrosh…
Models play an important role in our understanding of the global structure of the solar wind and its interaction with the interstellar medium. A critical ingredient in many types of models are the charge-exchange collisions between ions and…
Solar ionizing factors are responsible for modulation of interstellar neutral gas and its derivative populations inside the heliosphere. We provide an overview of the current state of knowledge about them for heliospheric particles inside…
Angular scattering in charge exchange and elastic collisions between interstellar ions and neutral (ISN) atoms has been assumed to be negligible in previous studies. Here, we investigated the momentum transfer associated with the angular…
Interstellar hydrogen atoms (H atoms) penetrate into the heliosphere through the region of the solar wind interaction with the interstellar plasma due to their large mean free path. Resonant charge exchange of H atoms with protons has been…
Shock boundary layers are regions bounded by a shock wave on the one side and tangential discontinuity on the other side. These boundary layers are commonly observed in astrophysics. For example, they exist in the regions of the interaction…
We estimate rate coefficients for charge transfer between neutral hydrogen and helium and moderate to highly ionized heavy elements. Although charge transfer does not have much influence on hot collisionally ionized plasmas, its effects on…
We investigate the charge transfer mechanism in the collisions of helium ions on nitric oxide using a molecular description framework with consideration of the orientation of the projectile toward the target. The anisotropy of the collision…
The heliosphere is predominantly a partially ionized plasma that consists of electrons, ions and significant neutral atoms. Nonlinear interactions amongst these species take place through direct collision or charge exchange processes. These…
Interstellar neutral atoms provide a remote diagnostic of plasma in the outer heliosheath and the very local interstellar medium via charge exchange collisions that convert ions into atoms and vice versa. So far, most studies of…
Absolute cross sections are measured for charge-exchange, ionization, and excitation within the same experimental setup for the Li$^{+}-$Ar, K$^{+}-$ Ar, and Na$^{+}-$ He collisions in the ion energy range $0.5-10$ keV. Results of our…
The Sun is moving through a warm ($\sim$6500 K) and partly ionized local interstellar cloud (LIC) with a velocity of $\sim$26 km/s. Recent measurements of the ionization of the LIC (Wolff et al., 1999) suggest that interstellar helium in…
We explore excitation and ionization by neutron impact as a novel tool for the investigation of electron-electron correlations in helium. We present single and double ionization spectra calculated in accurate numerical ab-initio simulations…
Helium ionization plays an important role in the energy balance of the upper chromosphere and transition region. Helium spectral lines are also often used as diagnostics of these regions. We carry out 1D radiation-hydrodynamics simulations…
We simulated the signal due to neutral He atoms, observed by Interstellar Boundary Explorer (IBEX), assuming that charge exchange collisions between neutral He atoms and He+ ions operate everywhere between the heliopause and a distant…
We study mutual ionization in collisions between atomic hydrogen and helium at impact velocities near the electronic threshold for this process (determined by the condition that kinetic energy of an equivelocity free electron is…
Aims. A model of heliosheath density and energy spectra of alpha-particles and He+ ions carried by the solar wind is developed. Neutralization of heliosheath He+ ions, mainly by charge exchange (CX) with neutral interstellar H and He atoms,…
The introduction of gases like nitrogen or neon for cooling the edge region of magnetically confined fusion plasmas has triggered a renewed interest in state selective cross sections necessary for plasma diagnostics by means of charge…
Collisionless shocks play a role in many astrophysical phenomena, from coronal mass ejections (CMEs) in the heliosphere to supernova remnants. Their role in heating and accelerating particles is well accepted yet the exact mechanism for ion…
The ionization state of the gas in the dynamic solar chromosphere can depart strongly from the instantaneous statistical equilibrium commonly assumed in numerical modeling. We improve on earlier simulations of the solar atmosphere that only…
The equation of state for hydrogen and helium is fundamental for studying stars and giant planets. It has been shown that because of interactions at atomic and molecular levels, the behaviour of a mixture of hydrogen and helium cannot be…