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Nonlinear numerical simulations are performed to investigate the density evolution in the dust layer of a protoplanetary disk due to the gravitational instability and dust settling toward the midplane. We assume the region where the radial…

Astrophysics · Physics 2009-11-11 Fumiharu Yamoto , Minoru Sekiya

Despite the phenomenal success of deep learning in recent years, there remains a gap in understanding the fundamental mechanics of neural nets. More research is focussed on handcrafting complex and larger networks, and the design decisions…

Machine Learning · Computer Science 2019-04-25 Saurav Basu , Koyel Mukherjee , Shrihari Vasudevan

For certain values of the wave speed parameter, evolution equations for the temperature of a region of fuel admit traveling wave solutions describing fire fronts. We consider such a system in the form of a nonlinear reaction-diffusion…

Pattern Formation and Solitons · Physics 2024-10-29 Olivia Chandrasekhar , Christopher K. R. T. Jones , Blake Barker , Rodman Linn

This study develops a statistical conditional approach to evaluate climate model performance in wind speed and direction and to project their future changes under the representative concentration pathway 8.5 scenario over inland and…

Applications · Statistics 2022-05-09 Qiuyi Wu , Julie Bessac , Whitney Huang , Jiali Wang

We investigate dust substructure formation induced by two super-Earths migrating in a low-viscosity disk with single-size dust grains selected from the submillimeter to centimeter range of sizes. The orbital evolution of planets takes place…

Earth and Planetary Astrophysics · Physics 2026-05-05 Zijia Cui , Ewa Szuszkiewicz

Context: Clumping in the radiation-driven winds of hot, massive stars arises naturally due to the strong, intrinsic instability of line-driving (the `LDI'). But LDI wind models have so far mostly been limited to 1D, mainly because of severe…

Solar and Stellar Astrophysics · Physics 2018-03-21 J. O. Sundqvist , S. P. Owocki , J. Puls

It is increasingly common for models of shallow-layer overland flows to include equations for the evolution of the underlying bed (morphodynamics) and the motion of an associated sedimentary phase. We investigate the linear stability…

Fluid Dynamics · Physics 2021-07-01 Jake Langham , Mark J. Woodhouse , Andrew J. Hogg , Jeremy C. Phillips

From geometry and conservation we derive two nonlinear evolution equations for sand ripples. In the case of a strong wind leading to a net erosion of the sand bed, ripples obey the Benney equation. This leads either to order or disorder…

Statistical Mechanics · Physics 2007-05-23 Zoltan Csahok , Chaouqi Misbah , Alexandre Valance

Traveling fronts and stationary localized patterns in bistable reaction-diffusion systems have been broadly studied for classical continuous media and regular lattices. Analogs of such non-equilibrium patterns are also possible in networks.…

Pattern Formation and Solitons · Physics 2012-10-29 Nikos E. Kouvaris , Hiroshi Kori , Alexander S. Mikhailov

A new mechanism for the evolution of primordial magnetic fields is described and analysed. The field evolution is followed from the time of its creation until the epoch of structure and galaxy formation. The mechanism takes into account the…

Astrophysics · Physics 2009-10-28 K. Dimopoulos , A. C. Davis

The thermodynamic structure of protoplanetary discs is determined by dust opacities, which depend on the size of the dust grains and their chemical composition. In the inner regions, the grain sizes are regulated by the level of turbulence…

Earth and Planetary Astrophysics · Physics 2021-06-30 Jonas Müller , Sofia Savvidou , Bertram Bitsch

Explaining the unexpected presence of dune-like patterns at the surface of the comet 67P/Churyumov-Gerasimenko requires conceptual and quantitative advances in the understanding of surface and outgassing processes. We show here that vapor…

Soft Condensed Matter · Physics 2017-03-09 P. Jia , B. Andreotti , P. Claudin

MHD turbulence plays a crucial role in the dust dynamics of protoplanetary discs. It affects planet formation, vertical settling and is one possible origin of the large scale axisymmetric structures, such as rings, recently imaged by ALMA…

Earth and Planetary Astrophysics · Physics 2018-10-03 A. Riols , G. Lesur

Wave-particle instabilities driven by departures from local thermodynamic equilibrium have been conjectured to play a role in governing solar wind dynamics. We calculate the statistical variation of linear stability over a large subset of…

Solar and Stellar Astrophysics · Physics 2020-01-08 Kristopher G. Klein , Mihailo Martinovic , David Stansby , Timothy S. Horbury

Vertical-axis wind turbines are great candidates to diversify wind energy technology, but their aerodynamic complexity limits industrial deployment. To improve the efficiency and lifespan of vertical axis wind turbines, we desire…

Fluid Dynamics · Physics 2023-03-30 Sébastien Le Fouest , Daniel Fernex , Karen Mulleners

Proto-planetary discs, the birth environment of planets, are an example of a structure commonly found in astrophysics, accretion discs. Identifying the mechanism responsible for accretion is a long-standing problem, dating back several…

Earth and Planetary Astrophysics · Physics 2023-04-04 Giovanni P. Rosotti

Motivated by the problem of the formation of active regions from a deep-seated solar magnetic field, we consider the nonlinear three-dimensional evolution of magnetic buoyancy instabilities resulting from a smoothly stratified horizontal…

Astrophysics · Physics 2009-11-13 Evy Kersale , David W. Hughes , Steven M. Tobias

Linear theory is a well developed framework for characterizing instabilities in weakly collisional plasmas, such as the solar wind. In the previous instalment of this series, we analyzed ~1.5M proton and alpha particle Velocity Distribution…

Solar and Stellar Astrophysics · Physics 2023-07-26 Mihailo M. Martinovic , Kristopher G. Klein

Vegetation in semi-arid environments self-organizes into striking spatial patterns -- bands, spots, labyrinths, and gaps -- with characteristic wavelengths on the order of tens to hundreds of meters. Existing reaction-diffusion models…

Pattern Formation and Solitons · Physics 2026-04-06 Chad M. Topaz

Ion irradiation during film growth has a strong impact on structural properties. Linear stability analysis is employed to study surface instabilities during ion-assisted growth of binary alloys. An interplay between curvature-dependent…

Materials Science · Physics 2015-05-30 Gintautas Abrasonis , Klaus Morawetz