# gst: self-mediation of runaway electrons via self-excited wave-wave and wave-particle interactions.

<< ️Nonlinear dynamics of runaway electron induced wave instabilities can significantly modify the runaway distribution critical to tokamak operations. Here (AA) present a fully kinetic simulation of runaway-driven instabilities toward nonlinear saturation in a warm plasma where collisional damping is subdominant. >>

<< ️It is found that the slow-X modes grow an order of magnitude faster than the whistler modes, and they parametrically decay to produce whistlers much faster than those directly driven by runaways. These parent-daughter waves, as well as secondary and tertiary wave instabilities, initiate a chain of wave-particle resonances that strongly diffuse runaways to the backward direction. This reduces almost half of the current carried by high-energy runaways, over a time scale orders of magnitude faster than experimental shot duration. These results beyond quasilinear analysis may impact anisotropic energetic electrons broadly in laboratory, space, and astrophysics. >>

Qile Zhang, Yanzeng Zhang, Qi Tang, et al. Self-mediation of runaway electrons via self-excited wave-wave and wave-particle interactions. Phys. Rev. E 113, L043203. Apr 20, 2026.

https://journals.aps.org/pre/abstract/10.1103/k3bq-cvjs

arXiv: 2409.15830v2 [physics.plasm-ph]. Mar 7, 2026.

https://arxiv.org/abs/2409.15830

Also: waves, particle, instability, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, waves, whistler waves, instability, particles, collisional damping, wave-particle resonance

# brain: hippocampus can rewires itself even after a single experience.

<< ️Understanding how brains learn and remember remains among the most important challenges in science. Recent studies in the hippocampus implicate a new form of synaptic plasticity, named behavioral timescale synaptic plasticity (BTSP), in the generation of experience-based learning and memory. BTSP is a strong, bidirectional type of plasticity that affects synaptic weights over many seconds of time. It is induced by single dendritic plateau potentials, as opposed to many action potentials, and is thus capable of producing new place cells in one trial. Plateau potential initiation is controlled, at least in part, by local feedback inhibition and an instructive input from a higher-order brain region that potentially links the plasticity to current experience.  >>

<< ️The new credit assignment procedure in BTSP provides a nonstandard mechanism for memory storage and retrieval that could mitigate the need for widespread synapse stabilization. In addition, it may allow hippocampal networks both to form memories of specific behavioral episodes and to generalize on the basis of past episodes. Finally, recent BTSP investigations could provide a basis for future explorations into how brains learn and remember, ranging from the systems and cognitive levels down to the basic biochemical building blocks of learning and memory. >>

Jeffrey C. Magee. Behavioral timescale synaptic plasticity: properties, elements and functions. Nature Neurosci 29; 520–534. Feb 20, 2026.

https://www.nature.com/articles/s41593-026-02214-2

Antoine D. Madar, Aaron D. Milstein, Thomas J. O’Dell, et al. Behavioral Timescale Synaptic Plasticity: A Burst in the Field of Learning and Memory. J. Neurosci .45 (46) e1332252025. Nov 12,  2025.

https://www.jneurosci.org/content/45/46/e1332252025

Yasemin Saplakoglu. A New Type of Neuroplasticity Rewires the Brain After a Single Experience. quantamagazine.org. Apr 24, 2026.

https://www.quantamagazine.org/a-new-type-of-neuroplasticity-rewires-the-brain-after-a-single-experience-20260424/

Also: brain, dance, in https://www.inkgmr.net/kwrds.html 

Keywords: brain, dance,  hippocampus, synaptic plasticity, behavioral timescale synaptic plasticity (BTSP), learning, memory, single dendritic plateau potentials, local feedback inhibition.

# gst: twin satellites and ring bubbles from coalescing magnetically levitated air bubbles in water.

<< ️(AA) investigate the ejection of satellite bubbles during the coalescence of two air bubbles in water. Using magnetic levitation (They) suspend the bubbles, with diameters in the range 3–15 mm, in a stable, neutrally buoyant state, free from mechanical constraints. >>

<< ️(Their) experiments reveal the simultaneous ejection of twin satellite bubbles from the poles of the bubble formed from the coalescence of equal-sized precursors. More generally, (They) find that the number and size of the ejected satellites are dependent on the initial size ratio of the precursor bubble pair. Numerical simulations, which agree well with (Their) experiments, show that satellite production is governed by the combined effect of two distinct processes: the arrival of a capillary wave crest at a pole and the rapid retraction of that polar region. >>

<< ️(They) propose a timing model that successfully predicts the range of size ratios for which single, double, or no satellites are formed. (Their) analysis also offers insight into the absence of satellite ejection in similarly sized liquid drop coalescence. Furthermore, (They) report the experimental observation of toroidal bubble ejection from precursor bubbles with approximately 2:1 diameter ratios, and (They) show that the formation of these toroidal bubbles is also governed by (Their) timing model. >>

N. Sampara, G. Hunter-Brown, K. A. Baldwin, et al. Twin satellites and ring bubbles from coalescing magnetically levitated air bubbles in water. Phys. Rev. Fluids 11, 043605. Apr 22, 2026.

https://journals.aps.org/prfluids/abstract/10.1103/fr1q-m1j9

Also: waves, drop, bubble, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, waves, capillary wave crest, drops, bubbles, twin satellite bubbles, toroidal bubbles, drop coalescence, satellite ejection.

# gst: transient chaos and Rayleigh particle escape out of a time modulated optical trap.

<< ️(AA) consider Rayleigh particles in a periodically modulated optical trap formed by two counterpropagating Gaussian beams. It is shown that for certain values of the parameters the system exhibits transient chaos which manifests itself in particle acceleration and subsequent directional ejection out of the trap. The escape flights are terminated at a distance of hundreds of wavelengths from the trap center and the particles return to the trap under the action of the Stokes force. The particle escape is shown to be a threshold effect that can be potentially employed for particle sorting. >>

Evgeny N. Bulgakov, Konstantin N. Pichugin, Dmitrii N. Maksimov. Transient chaos and Rayleigh particle escape out of a time modulated optical trap. Phys. Rev. E 113, 044216. Apr 23, 2026.

https://journals.aps.org/pre/abstract/10.1103/fj7q-vm5b

arXiv:2512.03403v1 [nlin.CD]. Dec 3, 2025.

https://arxiv.org/abs/2512.03403

Also: chaos, transition, particle, escape, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, chaos, transitions, particle, escape, periodically modulated trap, threshold effect.

# gst: chaotic ghosts in systems with parameter drift; delay and control critical transitions.

<< ️In dynamical systems with a time-dependent parameter, i.e., parameter drift, after crossing a saddle-node bifurcation, the so-called ghost state formed by the disappeared equilibria or periodic orbit can influence transient dynamics, causing a delayed transition. >>

<< ️This phenomenon has been investigated previously. However, the effect of chaotic ghosts on the critical transition in drifting systems has been less studied. In this paper, (AA) explore how chaotic ghosts and drifting rates influence critical transitions from the perspective of the ensemble. >> 

<< ️The (AA) results reveal the mechanism of the delayed transition related to chaos and how trajectories on the initial ensemble composed of a chaotic attractor transition to a qualitatively different object during the drift. In addition, (They) quantify the delayed transition and further find that the delay follows a power-law scaling with respect to the drifting rate. Finally, (AA) show that the critical transition is fully avoided as long as the reversal rate of the parameter exceeds a certain critical rate, even though the bifurcation point has been crossed. >>

Han Su, Denghui Li, Jicheng Duan, et al. Chaotic ghosts in systems with parameter drift: Delay and control critical transitions. Phys. Rev. E 113, 044207. April 13, 2026.

https://journals.aps.org/pre/abstract/10.1103/bdf8-wkpm

Also: chaos, attractor, transition,  in https://www.inkgmr.net/kwrds.html 

Keywords: gst, chaos, attractor, transitions, chaotic attractor transition, chaotic ghosts, criticality, critical transitions, bifurcation point, saddle-node bifurcation, ghost state, transient dynamics, delay, delayed transition, drifting rate.

# gst: quantum kicked top; a paradigmatic model

<< ️The quantum kicked top (QKT) is one of the most widely studied models in quantum chaos, providing a minimal yet powerful framework for exploring the relationship between classical nonlinear dynamics and quantum behavior. Unlike many chaotic systems with infinite-dimensional Hilbert spaces, the QKT possesses a finite-dimensional Hilbert space, making it analytically and numerically controllable while still showing a rich dynamical phenomena. >>

<< ️(AA) present a comprehensive introduction to the QKT as a paradigmatic model of quantum chaos. Starting from the classical kicked top, (They) derive the discrete nonlinear map governing the dynamics on the unit sphere and analyze its phase space structure through fixed points, stability analysis, bifurcations and Lyapunov exponents. (They) then discuss the role of symmetries, including rotational and time-reversal symmetry, and how their breaking modifies the dynamics. >>

<< ️By linking classical phase space structures with quantum dynamical indicators, the QKT provides a clear setting to investigate the emergence of chaotic behavior in the semiclassical limit. The chapter, therefore, highlights the quantum kicked top as a bridge between nonlinear classical dynamics, quantum chaos and modern quantum information science. >>

Avadhut V. Purohit, Udaysinh T. Bhosale. Quantum Kicked Top: A Paradigmatic Model. arXiv: 2604.12345v1 [quant-ph]. Apr 14, 2026.

https://arxiv.org/abs/2604.12345

Also: chaos, entropy, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, chaos, entropy, quantum kicked top, quantum chaos, bifurcations, rotational symmetry, time-reversal symmetry, entanglement, qubits, quantum information, entanglement entropy.

# gst: turbulent pair dispersion with stochastic generative diffusion models.

<< ️Recent advances in data-driven modeling have shown that diffusion models can successfully generate synthetic Lagrangian trajectories in turbulent flows. Building on this progress, (AA) extend the method to the joint generation of pairs of Lagrangian velocity trajectories, enabling a fully data-driven representation of turbulent pair dispersion, a long-standing fundamental problem with broad relevance in fluid dynamics. >>

<< ️(They) demonstrate that diffusion models accurately reproduce the evolution of particle-pair separation, including deviations from Richardson's classical scaling law, while simultaneously preserving all key single-particle statistical properties reported in previous studies. These findings underscore the potential of diffusion-based generative models to emulate high-dimensional, multi-scale turbulent dynamics, further establishing them as a powerful tool for scientific modeling and for future geophysical and astrophysical applications. >>

Pantera A., Biferale L., Buzzicotti M., et al. Turbulent pair dispersion with Stochastic Generative Diffusion Models. arXiv: 2604.12932v1 [physics.flu-dyn]. Apr 14, 2026.

https://arxiv.org/abs/2604.12932

Also: turbulence, waves, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, turbulence, waves, diffusion models, turbulent flows, turbulent pair dispersion, stochastic generative diffusion models (DM), direct numerical simulation (DNS).