ULF waves are MHD waves observed in the Earth's inner magnetosphere, especially oscillations with periods ranging from a few seconds to a few hundred seconds. The excitation and propagation processes of ULF waves have been extensively studied. Field line resonance (FLR) is a process in which Alfvén waves resonate with fast modes that are excited at the magnetopause and propagate toward the...
In computational plasma physics kinetic models are used to simulate plasma phenomena where small scale physics is expected to be of importance. These models contain the full information of the particle velocity distribution function but are computationally expensive. Therefore, computationally cheaper models are utilized, which can then be deployed to larger scales, e. g. 10-moment fluid...
The intricate energy exchanges within the Sun-Earth system, including geomagnetic storms, profoundly influence both ground and space technologies crucial for modern society. Effective forecasting and mitigation of space weather necessitate vigilant monitoring of the Earth's magnetosphere. However, this task is hindered by limited in-situ satellite measurements and ground-based observations....
Mirror waves are widely observed in space plasma environments. The mirror instability may occur in anisotropic plasmas where the perpendicular temperature exceeds the parallel temperature. An important characteristic of mirror waves is the anticorrelation between plasma density and magnetic field perturbations. Moreover, recent observations have indicated an anticorrelation between temperature...
Alfvén waves play an important role in coronal heating and solar wind acceleration. Despite the recent progress of theoretical and observational studies on Alfvén waves, their dissipation processes have not been fully understood. Parametric Decay Instability (PDI) is a coupling process between waves in which a large-amplitude, forward-propagating Alfvén wave resonates and decays into a...
Earth’s magnetosheath is a turbulent region where magnetosheath jets, localized dynamic pressure enhancements, are often observed. These magnetosheath jets form primarily at the quasi-parallel bow shock and move through the magnetosheath towards the magnetopause. Jets therefore transport mass, momentum, and energy across the magnetosheath. However, so far there are no estimates on the...
Galactic cosmic rays (GCRs) are charged particles with extremely high energies originating from outside the heliosphere. Their passage through the solar wind is affected by many long and short term factors, including transient structures such as coronal mass ejections (CMEs). The short term decrease in GCR flux caused by CMEs, and observed by charged particle detectors on spacecraft and...
Jets in active galactic nuclei (AGN) are known for their intense X-ray and gamma-ray emission, originating from non-thermal particles. These sources are also linked to high-energy neutrino events and are considered potential sites of ultra-high-energy cosmic ray production. Accelerated particles can be generated in shock waves formed in collisionless AGN plasmas. We study oblique mildly...
This study provides a new numerical method for relaxation of the Courant condition and correction of numerical errors in the Finite-Difference Time-Domain (FDTD) method with the time-development equations using higher-degree difference terms. The FDTD method (Yee 1966) is a numerical method for solving the time development of electromagnetic fields by approximating Maxwell's equations in both...
The objective of this project is to investigate shocks through Particle-In-Cell (PIC) simulations, particularly focusing on intermediate Mach. By delving into the transition between low and high Mach number instabilities, we aim to gain valuable insights into shock dynamics and electron behavior. Through experimentation and analysis, we hope to improve our understanding of shocks and electron...
In large-scale simulations, that also include spectral cosmic-ray physics, high-energy protons and electrons accelerated at the shocks of supernova remnants have to be described by a sub-grid model. Usually, the injected cosmic rays are represented by a simple power-law spectrum in momentum space. However, in the recent past several models for more realistic cosmic-ray spectra from supernova...
Plasma in space are omnipresent, but generally found in a partially ionized state only. Thus, we need to consider the interaction between ionized and neutral gases. Since the coupling between both gases is mediated via collisions we expect, on scales shorter than their collision frequency, the gases to increasingly decouple while on larger scales the gases to move in unison. This has immediate...
Variation of plasma density and magnetic field in space plasma drives the development of temperature anisotropies in the component species. A sufficiently large anisotropy of electrons in the direction perpendicular to the ambient magnetic field causes whistler and mirror instabilities to grow. It has been suggested that the anisotropy of the electron species can affect the growth of...
The exact plasma composition of astrophysical jets remains an open question to date. Jets originate near compact objects, protostars, and active galactic nuclei. Hence, the composition of the jets depends upon the environment in which they form, and it is expected that the composition should affect the dynamics and morphology of the jets. In this work, we aim to investigate the effect of...
Solar activities have an extraordinary impact on interplanetary space, enriching the plasma dynamics including turbulent heating of various species. The small fraction of alpha particles is believed to play a significant role in the turbulent dynamics of the solar wind. Here we present fully kinetic particle-in-cell (PIC) simulations to reveal the influences of the alpha particles in decaying...
Planetary radiation belts form a major hazard to orbiting satellites and predicting their variability is a primary goal of space weather forecasting efforts. While radiation belt dynamics are well-approximated by the Fokker Planck diffusion equation representing transport in energy, radial distance and pitch angle, more realistic magnetic field models and diffusive-advective transport have...
A 3D implicit particle-in-cell (PIC) simulation has been used to model the Earth’s magnetosphere to investigate the development of the ring current when electron kinetics are included. Initialized with starting conditions from a global magnetohydrodynamic (MHD) simulation, the computational burden for modeling the entire magnetosphere using a PIC code is reduced and allows the system to...
Historically, dark matter searches have primarily focused on hunting for effects from two-to-two scattering. However, given that the visible universe is primarily composed of plasmas governed by collective effects, there is great potential to explore similar effects in the dark sector. Recent semi-analytic work has shown that new areas of parameter space for dark U(1) and millicharged models...
Ultra-low frequency (ULF) waves contribute significantly to the dynamic evolution of Earth's magnetosphere by accelerating and transporting charged particles within a wide energy range. A substantial excitation mechanism of these waves is their drift-bounce resonant interactions with magnetospheric particles. Here, we extend the conventional drift-bounce resonance theory to formulate the...
Energy dissipation in collisionless plasmas is one of the most outstanding open questions in plasma physics. Magnetic reconnection and turbulence are two phenomena that can produce the conditions for energy dissipation. These two phenomena are closely related to each other in a wide range of plasmas. Turbulent fluctuations can emerge in critical regions of reconnection events, and magnetic...
Magnetic Reconnection is the ubiquitous astrophysical process in which a plasma rapidly converts magnetic field energy into a combination of flow energy, thermal energy and non-thermal energetic particles. Various particle acceleration mechanism (including Fermi acceleration, betatron acceleration, parallel electric field acceleration, out-of-reconnection plane acceleration) have been...
Context: The latest generation of radio telescopes, with their enhanced sensitivity and refined spatial resolution, are unveiling previously unidentified objects and capturing them with unprecedented details. One such enigmatic object is a radio galaxy located within the Abell 3266 cluster named "MysTail", observed as part of the MeerKAT Galaxy Cluster Legacy Survey. This galaxy exhibits...
TOI-700 d is the first Earth-sized planet in the habitable zone (HZ) discovered by the Transiting Exoplanet Survey Satellite. Here, we assess whether a Venus-like exoplanet at the TOI-700 d location could retain an atmosphere for a time comparable to the age of the host star based on multispecies magnetohydrodynamics simulations [1]. We investigate the effects of X-ray and EUV (XUV) radiation...
Magnetic fields can play an important role in the energy balance and formation of gas structures in galaxies. However, their dynamical effect on the rotation curve of galaxies is immensely unexplored. We investigate the dynamical impact of the known magnetic arms of NGC 6946 on its circular gas rotation traced in HI, considering two dark-matter mass-density models, ISO, and the universal NFW...
The phenomenon of energy dissipation in collisionless plasmas such as the solar wind remains a subject of incomplete understanding within the scientific community. Central to this enigma is the intermittent nature of magnetic structures, which seems to play a pivotal role in the energy cascade process. Achieving a comprehensive comprehension of energy transfer and dissipation in the solar wind...
We estimate the global impact of storms on the global structure and dynamics of the night side plasma sheet from observations by the NASA mission THEMIS. We focus on an intense storm occurring in December 2015 triggered by interplanetary coronal mass ejections (ICMEs). It starts with a storm sudden commencement (SSC) phase (SYM-H$\sim$+50nT) followed by a growth phase (SYM-H$\sim$-188 nT at...
