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The global structure of astrospheres: Effect of Knudsen number
Publications of the Astronomical Society of Australia. 2024. Vol. 41. Article e074.
Корольков С. Д., Vladislav Izmodenov
The interaction between stellar winds and the partially ionized local interstellar medium (LISM) is quite common in astrophysics. However, the main difficulty in describing the neutral components lies in the fact that the mean free path of an interstellar atom, l, can be comparable to the characteristic size of an astrosphere, L (i.e. the Knudsen number, which is equal to l/L, is approximately equal to 1, as in the case of the heliosphere). In such cases, a single-fluid approximation becomes invalid, and a kinetic description must be used for the neutral component. In this study, we consider a general astrosphere and use a kinetic-gas dynamics model to investigate how the global structure of the astrosphere depends on the Knudsen number. We present numerical results covering an extremely wide range of Knudsen numbers (from 0.0001 to 100). Additionally, we explore the applicability of single-fluid approaches for modelling astrospheres of various sizes. We have excluded the influence of interstellar and stellar magnetic fields in our model to make parametric study of the kinetic effects feasible. The main conclusion of this work is that, for large astrospheres (with a distance to the bow shock greater than 600 AU) a heated rarefied plasma layer forms in the outer shock layer near the astropause. The formation of this layer is linked to localized heating of the plasma by atoms (specifically, ENAs) that undergo charge exchange again behind the astropause. This process significantly alters the flow structure in the outer shock layer and the location of the bow shock, and it cannot be described by a single-fluid model. Additionally, this paper discusses how atoms weaken the bow shocks at near-heliospheric conditions.
Dmitriev A., Kornilov V., Batienkov R., Lecture Notes in Civil Engineering 2026 Vol. 886 P. 249–255
Numerous studies have provided compelling evidence that the probability distribution of avalanche sizes follows a power law, and that 1/f noise is present in the stochastic dynamics of landslides. We present a theoretical explanation of these phenomena within the framework of self-organized criticality theory, proposing a discrete-time model in the form of a sandpile cellular ...
Added: October 13, 2026
Dmitriev A., Shulman I., Lebedev A., Studies in Computational Intelligence 2026 Vol. 1265 P. 266–273
A discrete-time model is presented for the self-organization of the X/Twitter social network to the edge of a phase transition, characterized by avalanche-like propagation of information in the network. The model is based on the analogy between the critical dynamics of the X social network and sandpile cellular automata with Manna rule on the Chung-Lu ...
Added: October 13, 2026
Arutyunov K., Kharitonov I. A., Petrosyants K. O., JETP Letters 2026 Vol. 124 No. 6 P. 1–16
Superconducting properties of metallic micro- and nanowires can be entirely different from those of bulk superconductors. Of particular interest is the nonequilibrium current-induced state of a quasi-one-dimensional superconducting channel. The most interesting phenomenon here is the stepped I–V characteristic, explained by a process known as phase slip center activation. If the origin of such step-like ...
Added: October 13, 2026
Makarov D. M., Kalikin N., Fashchevsky K. A. et al., Electrochimica Acta 2026 Vol. 579 Article 150159
Machine learning (ML) has become a powerful tool for accelerating the development of carbon-based supercapacitors;
however, most published models assume that a single predictive framework can describe both conventional
porous carbons and hybrid carbon electrodes. Here, we test this assumption using a comprehensive
benchmark dataset and an extended literature-curated dataset enriched with synthesis- and electrolyte-related
descriptors. Three ML algorithms ...
Added: October 13, 2026
Махлуф М., Ozhegov R., Elezov M. et al., Фотоника 2026 Vol. 20 No. 6 P. 414–423
This paper compares the ranging precision of direct time-of-flight (dToF) and non-line-of-sight (NLOS) LiDAR architectures, both using a superconducting nanowire single-photon detector (SNSPD). Both systems operate at 1550 nm with a 50 ps pulsed laser and time-correlated single-photon counting (TCSPC). The dToF configuration achieved approximately 100 µm precision at 10 m, while the NLOS configuration achieved 500 µm precision for ...
Added: October 12, 2026
Singapore: Springer, 2026.
This volume presents the Proceedings of the 34th IUPAP Conference on Computational Physics (CCP2023), held in Kobe, Japan on August 4–8, 2023. It offers a collection of peer-reviewed articles that highlight recent developments in computational and simulation research across various areas of physics. Key topics include the use of data science, quantum computing, and machine ...
Added: October 12, 2026
Goncharov A., Chibisov A., Advanced Theory and Simulations 2023 Vol. 12 No. 13 Article 2200816
Designing stable quantum computers with the ability to correct errors responsibly requires a detailed understanding of the physical processes that underlie these devices. In this study, detailed quantum mechanical simulations of the atomic structure, charge distribution of electron density, and distribution and orientation of magnetic and quantum states as a function of applied external pressure ...
Added: October 11, 2026
Chibisov A., Gnidenko A., Chibisova M. et al., FlatChem 2023 Vol. 41 Article 100533
Manufacturing precise quantum computers with small errors in quantum operations, long coherence times, and low power consumption is the most important challenge in modern nanoelectronics. To understand the operating modes of such calculators in detail, both the optimal arrangement of the qubit system within the structure and changes in its magnetic properties must be comprehensively ...
Added: October 11, 2026
Kornbleuth M., Opher M., Drake J. F. et al., Astrophysical Journal 2026 Vol. 1004 No. 1 Article 1
The shape of the heliosphere, regarded as comet-like since the 1960s, has recently been the subject of intense debate in the last decade. There is disagreement as to whether the heliospheric tail extends to ∼10,000 au in a comet-like shape or if it is short (∼400 au) with a split. Energetic neutral atom (ENA) maps from ...
Added: June 3, 2026
Anastasia Titova, Izmodenov V., Sergey Korolkov, Advances in Space Research 2026 Vol. 78 No. 2 P. 1702–1710
Solar Ly-alpha photons are scattered by interstellar hydrogen (H) atoms that penetrate into the heliosphere through the region of the solar wind interaction with the local interstellar medium. The spectra of scattered Ly-alpha reflect the properties of the velocity distribution of the interstellar H atoms. The spectra of backscattered Ly-alpha have been reconstructed in anti-sunward ...
Added: May 15, 2026
Sergey D. Korolkov, Igor I. Baliukin, Opher M., Advances in Space Research 2026 Vol. 77 No. 6 P. 7443–7454
Global ideal magnetohydrodynamic models of the heliosphere typically predict a greatly exaggerated magnetic field pile-up in the inner heliosheath (IHS), the region between the termination shock and heliopause. However, Voyager 1 and 2 observations show only a gradual increase throughout this region. This mismatch is largely attributed to the simplified assumption of a unipolar solar ...
Added: February 27, 2026
Li H., Yang Z., Wang C. et al., Journal of Deep Space of Exploration 2025 Vol. 12 No. 5 P. 489–502
In this paper, the main scientific objectives, observational requirements, and expected scientific returns of boundary exploration missions in different directions, such as the heliospheric nose and tail, were briefly introduced; the current research status at home and abroad was reviewed, including ongoing and proposed missions and their scientific payload configurations; several major scientific questions related ...
Added: February 11, 2026
A. V. Titova, S. D. Korolkov, V. V. Izmodenov, Lobachevskii Journal of Mathematics 2025 Vol. 46 No. 9 P. 4526–4533
The stability of the heliopause, the tangential discontinuity separating the solar wind from the interstellar medium, is influenced by various processes, including the Kelvin–Helmholtz instability. This study investigates the role of charge exchange collisions between protons and hydrogen (H) atoms in reduction of the Kelvin–Helmholtz growth rate at the heliopause. Using a two-dimensional gasdynamic model ...
Added: January 12, 2026
Sergey Korolkov, Vladislav Izmodenov, Publications of the Astronomical Society of Australia 2025 Vol. 42 Article e123
Recently, there have been discussions about the shape of the heliopause. Some scientists question the classical form, which is close to a paraboloid. They suggest that the heliopause may have a two-jet collimated shape. While we disagree with this view of the heliopause shape, it seems likely that for stars with stronger stellar magnetic fields ...
Added: September 4, 2025
Baliukin I., Izmodenov V., Advances in Space Research 2025 Vol. 76 No. 3 P. 1917–1938
One of the most remarkable discoveries by the Interstellar Boundary Explorer (IBEX) is the ribbon – a narrow band of enhanced energetic neutral atom (ENA) fluxes observed in the sky. The prevailing explanation attributes the IBEX ribbon to the secondary ENA mechanism. In this process, “primary” hydrogen ENAs, produced via charge exchange between solar wind protons and interstellar hydrogen ...
Added: August 12, 2025
Viktor A. Frantsuzov, Artemyev A., Shi X. et al., Astrophysical Journal 2024 Vol. 963 No. 1 Article 16
The investigation of mechanisms responsible for the heating of cold solar wind electrons around the Earth’s bow shock is an important problem in heliospheric plasma physics because such heating is vitally required to run the shock drift acceleration at the bow shock. The prospective mechanism for electron heating is magnetic pumping, which considers electron adiabatic ...
Added: April 25, 2025
A.V. Titova, V.V. Izmodenov, S.D. Korolkov, Publications of the Astronomical Society of Australia 2025 Vol. 42 Article e045
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 considered as the main interaction process between the components. In the majority of models, other processes like ...
Added: April 22, 2025
Sheveleva D., Апатенков С. В., Сахаров Я. А. et al., Космические исследования 2023 Т. 61 № 1 С. 39–42
140 events with the largest amplitudes of geomagnetically induced currents (GIC) at the Vykhodnoy station (65 MLat) registered in 2012-2018 were investigated. The significant differences between the parameters of the solar wind and geomagnetic indices from typical values are shown. Characteristic increases in solar wind velocity and dynamic pressure are visible, and the Bz component ...
Added: March 29, 2025
Зелёный Л. М., Захаров А. В., Popel S. et al., Успехи физических наук 2024 Т. 194 № 6 С. 569–599
We review studies of physical processes associated with the impact of external factors in outer space — flows of micrometeoroids and solar radiation — on the lunar regolith. Under the influence of these factors, regolith microparticles can detach from the surface and levitate. Near-surface plasma and levitating dust particles form a plasma-dust exosphere of the ...
Added: July 31, 2024
Шохрин Д. В., Копнин С. И., Popel S., Письма в Журнал экспериментальной и теоретической физики 2024 Т. 119 № 6 С. 419–425
It has been shown that a dusty plasma is formed in a layer over the illuminated surface of Saturn’s moon Enceladus
due to photoelectric and electrostatic processes. Using a physicomathematical model to self-consistently
describe the densities of photoelectrons and dust particles over the illuminated surface of Enceladus,
distribution functions of photoelectrons near the surface, as well as the ...
Added: June 14, 2024
Florinski V., Guzman J. A., Kleimann J. et al., Astrophysical Journal 2024 Vol. 961 No. 2 Article 244
This paper examines the geometry of interstellar magnetic field lines close to the boundary of the heliosphere in the direction of the unperturbed local interstellar magnetic field, where the field lines are spread apart by the heliopause (HP). Such field parting establishes a region of weaker magnetic field of about 300 au in size in ...
Added: January 31, 2024
Powell E., Opher M., Kornbleuth M. et al., Astrophysical Journal 2024 Vol. 961 No. 2 Article 235
Lyα absorption profiles have been used to detect astrospheres and heliospheric absorption from the hydrogen wall and heliotail. Using magnetohydrodynamic models of the heliosphere, we can compare simulated to observed Lyα profiles to probe the neutral hydrogen within and near the heliosphere. There is an ongoing controversy whether the heliosphere has a long “comet-like” tail ...
Added: January 31, 2024
Izmodenov V., Sterken V., Baalmann L. et al., Space Science Reviews 2022 Vol. 218 Article 71
Interstellar dust particles were discovered in situ, in the solar system, with the Ulyssesmission’s dust detector in 1992. Ever since, more interstellar dust particles have been measured inside the solar system by various missions, providing insight into not only the composition of such far-away visitors, but also in their dynamics and interaction with the heliosphere. The ...
Added: January 30, 2024
S. I. Popel, Golub' A. P., L. M. Zelenyi, Physics of Plasmas 2023 Vol. 30 No. 4 Article 043701
Above the sunlit surface of Mercury, the properties and formation of dusty plasmas are investigated. It is demonstrated that the dusty plasmas are formed for subsolar angles exceeding approximately 76^o due to photoelectric and electrostatic processes. As a result, the dusty plasmas are present in the polar regions of Mercury, characterized by latitudes of about 70^o and above. The formation ...
Added: April 3, 2023