Arian Ojeda González

In this work, we present the development of the Tonalli code: a simplified multispecies (H I , H II , H ⁻ , and e ) magnetohydrodynamic (MHD) model in non–local thermodynamic equilibrium (NLTE) focused on solar chromospheric conditions. This new model integrates two well-established models, Newtonian CAFE (MHD) and PakalMPI (NLTE), through a self-convergence system that links the state equations used by both codes to calculate density, pressure, and temperature, with the mean molecular weight ( μ ) serving as a proxy. Newtonian CAFE computes the plasma variables using the ideal MHD, while PakalMPI calculates the species densities of neutral hydrogen (H I ), protons (H II ), negative hydrogen (H ⁻ ), and electrons ( n _e ) under the NLTE approximation. We used Tonalli to test the stability of the hydrostatic C7 model, covering 3000 km of the solar chromosphere with a vertical constant field of 30 G and a vertical constant gravity field of 274.0 ms ⁻² . As a result, Tonalli generates 3D cubes of densities, temperature, pressure, mean molecular weight, and the departure coefficient of hydrogen in its first energy level b ₁ , providing a detailed representation of the ionization states of the plasma at chromosphere altitudes. Despite the fact that MHD conditions can lead to numerical diffusion of the plasma, we demonstrate robustness and consistency, and self-convergence of the model with the relative error of electron density reaching values of 3.7 × 10 ⁻⁷ .

The Grad-Shafranov (GS) equation is a fundamental tool extensively used in plasma physics, particularly in the context of magnetic confinement, notably in tokamaks for fusion energy research. This equation plays a crucial role in reconstructing magnetic field topology in plasma regions like the magnetopause and magnetotail, leading to the development of the GS reconstruction technique. In this third installment of our series, we explore the merger of the Yoon-Lui-2 and Yoon-Lui-3 generating functions, allowing for a deeper understanding of the core equation in Plasma Physics. Furthermore, this article provides a comprehensive summary of solutions previously presented in Parts 1 and 2. We investigate the behavior of magnetic islands positioned above either the X-axis or the Z-axis for specific parameter values and their impact on plasma confinement. The article concludes that the derived model offers a simpler, more stable, and easily analyzable solution for magnetic morphology. However, it is worth noting that the model’s inflexibility in singularity positions may limit its adaptability to different scenarios. This article marks the conclusion of our physics education series dedicated to studying new specific solutions of the GS equation.

In part 1 of our physics education series, we introduced a novel solution based on Yoon-Lui’s solutions 1 and 2. Building upon that, this follow-up presents a new solution obtained by combining the generating functions of Yoon-Lui-1 and Yoon-Lui-3, resulting in a new and simplified general solution. We also calculate the singular points and determine their coordinates for various parameter values. A graphical representation of the solution is presented, showing the magnetic field lines and current density distribution. The behavior of the magnetic field and the effect of varying the parameter are discussed. The observed magnetic islands and singular points are relevant in the fields of Plasma Physics and Space Physics, providing insights into magnetic structures in plasmas and their impact on confinement and stability. Furthermore, this study encourages innovation and equips researchers and students with the necessary tools to make meaningful contributions to the field, emphasizing the integration of scientific literature into physics education to promote a comprehensive understanding of physical concepts and their practical applications.

This article provides a comprehensive review of relevant studies in the fields of plasma physics, electromagnetism, and space physics. The aim is to demonstrate how the study of the scientific literature can be used to enhance problem-solving abilities and develop innovative solutions in physics. In this paper, we focus on the study of solutions of the specific Grad-Shafranov equation. Two of the new solutions proposed by Yoon and Lui (2005) are used as a basis for the development of a new solution. The new solution presented has singular points similar to the Yoon-Lui-2 solution, but with an inverted configuration, and also presents less rounded double islands compared to the Yoon-Lui-2 solution. Additionally, the new solution does not exhibit the formation of a current ring, a characteristic of the Yoon-Lui-1 solution, and varying its parameters may lead to higher plasma confinement efficiency. In summary, we illustrate how a thorough analysis of literature can serve as a powerful means for generating innovative approaches to resolving theoretical issues in physics.

En este artículo trabajamos con la ecuación de velocidad de un fluido magneto-conductor utilizando dos aproximaciones: (i) la ley de Ampère y (ii) tomando en cuenta la corrección de Maxwell. Considerando una dirección arbitraria entre el vector de onda y el campo magnético se obtiene una expresión para la velocidad de fase de la onda. Existen tres modos de onda magnetohidrodinámicas (MHD) cuando la corriente de desplazamiento (Jd) no es considerada. Primero, se hace una comparación de los modos de onda entre sí, y después se comparan con los modos obtenidos con y sin la Jd. La comparación, permite discutir las variaciones entre estos modos MHD en los casos teóricos, cuando la velocidad de Alfvén aumenta hasta valores cercanos a la velocidad de la luz. El objetivo principal del artículo es mostrar la importancia del efecto de la Jd en los modos puro y rápido de ondas MHD, en el caso particular en donde la velocidad de Alfvén es mayor que la velocidad adiabática de una onda acústica. Encontramos que para el modo lento, la Jd prácticamente no influye en el valor de la velocidad de fase de la onda cuando la velocidad de Alfvén aumenta.

O artigo visa o desenvolvimento de um novo algoritmo via Python para estudar eventos de Atividade Auroral Contínua do Índice AE (Eletrojato Auroral), de Grande Intensidade e Longa Duração, HILDCAAs e HILDCAAs* (no qual * corresponde ao fenômeno HILDCAA flexibilizado). Este algoritmo é baseado e validado por meio do algoritmo previamente desenvolvido por Prestes et al. (2017a) em MATLAB. O intuito deste novo algoritmo proposto aqui é tornar o fluxograma deste acessível a todos os usuários, além de complementar e atualizar o algoritmo em MATLAB já existente. Um importante aspecto é o fato da linguagem de programação de alto nível Python ser uma ferramenta gratuita. Ademais, o artigo também objetiva a comparação dos eventos encontrados no ano de 1998 neste trabalho com aqueles obtidos por Prestes et al. (2017a) e Guarnieri (2006). A nova flexibilização adotada aqui não tem a intensão de suprimir ou modificar a concepção original das HILDCAAs, mostra que os eventos encontrados aqui continuam associados aos fenômenos HSSs/CIRs (Feixes Rápidos do Vento Solar/Regiões de Interações Corrotantes).