arXiv subjects

Mohammed H. Talafha

Publications and source records attributed to Mohammed H. Talafha.

5 recordsLinked to original sources

arXiv2026

Investigating Nonlinear Quenching Effects on Polar Field Buildup in the Sun Using Physics-Informed Neural Networks

The solar dynamo relies on the regeneration of the poloidal magnetic field through processes strongly modulated by nonlinear feedbacks such as tilt quenching (TQ) and latitude quenching (LQ). These mechanisms play a decisive role in regulating the buildup of the Sun's polar field and, in turn, the amplitude of future solar cycles. In this work, we employ Physics-Informed Neural Networks (PINN) to solve the surface flux transport (SFT) equation, embedding physical constraints directly into the neural network framework. By systematically varying transport parameters, we isolate the relative contributions of TQ and LQ to polar dipole buildup. We use the residual dipole moment as a diagnostic for cycle-to-cycle amplification and show that TQ suppression strengthens with increasing diffusivity, while LQ dominates in advection-dominated regimes. The ratio $ΔD_{\mathrm{LQ}}/ΔD_{\mathrm{TQ}}$ exhibits a smooth inverse-square dependence on the dynamo effectivity range, refining previous empirical fits with improved accuracy and reduced scatter. The results further reveal that the need for a decay term is not essential for PINN set-up due to the training process. Compared with the traditional 1D SFT model, the PINN framework achieves significantly lower error metrics and more robust recovery of nonlinear trends. Our results suggest that the nonlinear interplay between LQ and TQ can naturally produce alternations between weak and strong cycles, providing a physical explanation for the observed even-odd cycle modulation. These findings demonstrate the potential of PINN as an accurate, efficient, and physically consistent tool for solar cycle prediction.

astro-ph.SR↗

arXiv2026

Abundance Calculations of Neon Isotopes in the Predicted Lifetime of the Sun

The elemental abundances of neon isotopes provide valuable insights into stellar evolution and nucleosynthesis. In this study, we calculate the abundances of the isotopes 18Ne, 19Ne, 20Ne, 21Ne, and 22Ne across the five principal evolutionary phases of the Sun: hydrogen burning, lively old age, onset of rapid growth and red giant, helium burning and helium exhaustion. The calculations were carried out using the open-source nucnet-tools package, developed by the Webnucleo Group at Clemson University. Initial isotope abundances were adopted from standard proto-solar compositions. Their evolution was computed under static hydrostatic burning conditions, assuming constant temperature and density within each phase. The results show that the stable isotopes 20Ne and 22Ne remain dominant throughout the Sun's lifetime, whereas the short-lived isotopes 18Ne and 19Ne decay rapidly during or shortly after the hydrogen-burning phase. The predictions obtained for the helium burning and exhaustion phases provide quantitative neon-isotope abundances that are not extensively reported in the existing literature. These results offer valuable reference values for future studies of solar and stellar evolution, nucleosynthetic pathways, and isotopic modeling.

astro-ph.SR↗

arXiv2025

Modelling the Solar Cycle Nonlinearities into the Algebraic Approach

Understanding and predicting solar-cycle variability requires accounting for nonlinear feedbacks that regulate the buildup of the Sun's polar magnetic field. We present a simplified but physically grounded algebraic approach that models the dipole contribution of active regions (ARs) while incorporating two key nonlinearities: tilt quenching (TQ) and latitude quenching (LQ). Using ensembles of synthetic cycles across the dynamo effectivity range $λ_R$, we quantify how these mechanisms suppress the axial dipole and impose self-limiting feedback. Our results show that (i) both TQ and LQ reduce the polar field, and together they generate a clear saturation (ceiling) of dipole growth with increasing cycle amplitude; (ii) the balance between LQ and TQ, expressed as $R(λ_R) = \mathrm{dev(LQ)}/\mathrm{dev(TQ)}$, transitions near $λ_R \approx 12^\circ$, with LQ dominating at low $λ_R$ and TQ at high $λ_R$; (iii) over $8^\circ \leq λ_R \leq 20^\circ$, the ratio follows a shallow offset power law with exponent $n \approx 0.36 \pm 0.04$, significantly flatter than the $n=2$ scaling assumed in many surface flux--transport (SFT) models; and (iv) symmetric, tilt-asymmetric, and morphology-asymmetric AR prescriptions yield nearly identical $R(λ_R)$ curves, indicating weak sensitivity to AR geometry for fixed transport. These findings demonstrate that nonlinear saturation of the solar cycle can be captured efficiently with algebraic formulations, providing a transparent complement to full SFT simulations. The method highlights that the LQ\--TQ balance is primarily controlled by transport ($λ_R$), not by active-region configuration, and statistically disfavors the SFT-based $1/λ_R^{2}$ dependence.

astro-ph.SR↗

arXiv2025

Effect of Nonlinear Surface Inflows into Activity Belts on Solar Cycle Modulation

Converging flows are visible around bipolar magnetic regions (BMRs) on the solar surface, according to observations. Average flows are created by these inflows combined, and the strength of these flows depends on the amount of flux present during the solar cycle. In models of the solar cycle, this average flow can be depicted as perturbations to the meridional flow. In this article, we study the effects of introducing surface inflow to the surface flux transport models (SFT) as a possible nonlinear mechanism in the presence of latitude quenching for an inflow profile whose amplitude varies within a cycle depending on the magnetic activity. The results show that including surface inflows in the model in the presence of both LQ and tilt quenching (TQ) produced a polar field within a $\pm$1$σ$ of an average cycle polar field ($σ$ is the standard deviation) and a correlation coefficient of 0.85. We confirm that including inflows produces a lower net contribution to the dipole moment (10\,--\,25\%). Furthermore, the relative importance of LQ vs. inflows is inversely correlated with the dynamo effectivity range ($λ_{R}$). With no decay term, introducing inflows into the model resulted in a less significant net contribution to the dipole moment. Including inflows in the SFT model shows a possible nonlinear relationship between the surface inflows and the solar dipole moment, suggesting a potential nonlinear mechanism contributing to the saturation of the global dynamo. For lower $λ_R$ ($\lessapprox$ 10 $^\circ$), TQ always dominates LQ, and for higher $λ_R$ LQ dominate. However, including inflows will make the domination a little bit earlier in case of having a decay term in the model.

astro-ph.SR↗

arXiv2019

Symbols and astrological terms in ancient arabic inscriptions

In the past, the Arabs in Al-Hara Zone used many stars to deduce the seasons of the year and also to deduce the roads, at that time this was the most convenient way to figure their ways and to know the time of the year they have to travel or to planet, The most important used stars at that time were the Pleiades, Canopus, Arcturus, and other stars. This study shows the inscriptions found in Al-Hara Zone in many field trips in the year 2018 which were written on smooth black rocks and how these inscriptions related to the stars and to the seasons - at that time - of the year.

physics.hist-ph↗