Article
Astronomy & Astrophysics
James Wurster
Summary: Research shows that in protostellar discs, the Hall effect is typically the dominant factor, with Ohmic resistivity and ambipolar diffusion coefficients being similar in magnitude, indicating that both are equally important and omitting either one would lead to a misunderstanding of disc evolution.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Haifeng Yang, Xue-Ning Bai
Summary: Recent studies have shown that the evolution of protoplanetary disks is primarily driven by magnetized disk winds, with the size of the disks shrinking over time and magnetic flux loops driving expansion. These magnetic flux loops gradually shrink, with rates depending on disk magnetization and external environment, ultimately governing the long-term disk evolution.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
A. Tritsis, C. Federrath, K. Willacy, K. Tassis
Summary: Non-ideal magnetohydrodynamic effects are crucial in understanding the formation of stars. In this study, we modify the FLASH code to include a detailed treatment of non-ideal MHD and investigate its role in collapsing pre-stellar cores. Our simulations show that the ion responsible for most of the conductivities is D-3(+), rather than H-3(+) as previously thought.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Mechanics
Claudio Cremaschini, Jiri Kovar, Zdenek Stuchlik, Massimo Tessarotto
Summary: This article reviews the original thermodynamic formulation of the Tolman-Ehrenfest effect and discusses the different statistical temperature distributions and their properties in non-ideal fluids.
Article
Physics, Multidisciplinary
Nuris Figueroa-Morales, Mikhail M. Genkin, Andrey Sokolov, Igor S. Aranson
Summary: In this study, the authors demonstrate the control of topological defects in a living liquid crystal by introducing microscopic obstacles. They find that negative defects can be immobilized while positive defects remain motile. This immobilization is attributed to the attraction between opposite defects.
COMMUNICATIONS PHYSICS
(2022)
Article
Physics, Fluids & Plasmas
C. Nuehrenberg
Summary: The study investigated the effect of subsonic flow on the ideal magnetohydrodynamic stability of most stellarators, implementing a mathematical formulation of the weak form of stability equations with flow in CAS3D. The findings revealed the presence of unstable flow-induced continua and stable modes influenced by sheared flow in stellarators.
PLASMA PHYSICS AND CONTROLLED FUSION
(2021)
Article
Astronomy & Astrophysics
Yoshihiro Kawasaki, Shunta Koga, Masahiro N. Machida
Summary: This study investigates the impact of dust growth on non-ideal magnetohydrodynamic effects during the collapse of a cloud core, taking into account both dust coagulation and dust fragmentation. The results show that both processes are necessary to activate the non-ideal magnetohydrodynamic effects, which play a significant role in star and disc formation processes.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Physics, Fluids & Plasmas
Yi-Min Huang, Yao Zhou, Joaquim Loizu, Stuart Hudson, Amitava Bhattacharjee
Summary: Singular currents appear on rational surfaces in non-axisymmetric ideal MHD equilibria, with a surface current preventing magnetic islands and a divergent Pfirsch-Schluter current density when pressure gradient is present. In traditional treatment, the Pfirsch-Schluter current scales as J similar to 1/Delta iota on adjacent flux surfaces, leading to a paradox. This study investigates this issue by considering the pressure-gradient-driven singular current in the Hahm-Kulsrud-Taylor problem and shows that the total current is finite due to the formation of a Dirac delta-function current sheet at the rational surface, resolving the paradox. The strong packing of flux surfaces causes a steepening of the pressure gradient near the rational surface.
PLASMA PHYSICS AND CONTROLLED FUSION
(2023)
Article
Astronomy & Astrophysics
Kenji Eric Sadanari, Kazuyuki Omukai, Kazuyuki Sugimura, Tomoaki Matsumoto, Kengo Tomida
Summary: Magnetic fields play important roles in star formation, and strong fields can be generated by turbulent dynamo. The non-ideal magnetohydrodynamic simulations show that magnetic field growth can be slightly suppressed by ambipolar diffusion, but it has no effect on temperature evolution. The resulting magnetic field strength is stronger than in the present-day cases. The impact of the magnetic field on dynamics during the later accretion phase is smaller.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Optics
B. Hoeckendorf, A. Alvermann, H. Fehske
Summary: We propose a one-dimensional Floquet ladder with two distinct topological transport channels of opposite directionality, controlled externally by focusing light beams into adjacent waveguides. The direction of transport is determined by the relative phase and angles of incidence of the light beams, with the mechanism found to be robust against disorder.
Article
Materials Science, Multidisciplinary
Pascal M. Vecsei, M. Michael Denner, Titus Neupert, Frank Schindler
Summary: In this study, non-Hermitian band structures are characterized using symmetry indicator topological invariants, which provide a shortcut for calculating traditional non-Hermitian topological invariants. The authors demonstrate that symmetry indicators can characterize the associated Chern-Simons form in time-reversal symmetric non-Hermitian topological insulators, simplifying the evaluation process. Additionally, the study discusses non-Hermitian surface states associated with nontrivial symmetry indicators.
Article
Mathematics, Applied
Randheer Singh, Sarswati Shah, Jasobanta Jena
Summary: This manuscript examines the advancement of one-dimensional shock waves propagating through a non-ideal reacting gas. By considering the shock wave as a propagating discontinuity surface, a pair of evolution equations describing the shock strength and first-order discontinuity for variable initial data are derived. Truncation approximations are used to obtain the shock velocity exponent and compared with those obtained from Guderley's scheme and Chisnell-Chester-Whitham (CCW) rule. The effects of non-ideal and reaction parameters on the shock evolution in the case of arbitrary shock strength are analyzed and compared with the results from the CCW rule. Furthermore, the global behaviors of shock strength and induced discontinuity for different values of non-ideal and reaction parameters are examined.
MATHEMATICAL METHODS IN THE APPLIED SCIENCES
(2023)
Article
Computer Science, Artificial Intelligence
Milan Matejdes
Summary: The article discusses the correspondence between soft ideal topological spaces and ideal topological spaces, and applies methods from general topology to study soft omega open sets and strongly soft omega open sets.
Article
Multidisciplinary Sciences
Rujiang Li, Bo Lv, Huibin Tao, Jinhui Shi, Yidong Chong, Baile Zhang, Hongsheng Chen
Summary: In this study, a topological circuit with only four ideal type-II Weyl points was experimentally realized by stacking layers of inductor-capacitor resonators with broken parity inversion symmetry. This system provides an ideal platform for further research on Weyl physics and other exotic topological phenomena, due to its unique spectral characteristics and topological surface states.
NATIONAL SCIENCE REVIEW
(2021)
Article
Physics, Applied
Sk Jamaluddin, Subir Sen, Dola Chakrabartty, Ajaya K. Nayak
Summary: This study presents the finding of two types of distinct Hall signals in single crystalline Hall devices of a D-2d symmetric antiskyrmion host Mn-Ni-Ga sample. One is the topological Hall signal originating from the antiskyrmion phase, and the other is the two-component anomalous Hall effect arising due to the presence of twinning microstructure.
APPLIED PHYSICS LETTERS
(2023)
