Circulation of energetic ions within Ganymede’s magnetosphere: a Monte-Carlo simulation approach

2021 ◽  
Author(s):  
Christina Plainaki ◽  
Stefano Massetti ◽  
Xianzhe Jia ◽  
Alessandro Mura ◽  
Anna Milillo ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Monte Carlo ◽  
Plasma Sheet ◽  
Monte Carlo Model ◽  
Weather Conditions ◽  
The Moon ◽  
Water Release ◽  
Energetic Ions ◽  
Surface Precipitation ◽  
Long Term Impact

<p>The study of Ganymede, the only known moon in the Solar System to possess an intrinsic magnetic field embedded within a planetary magnetosphere, is of significant importance in view of future missions to the Jovian system. Indeed, the dynamics of the entry and circulation inside Ganymede’s magnetosphere of the Jovian energetic ions, as well as the morphology of their precipitation on the moon’s surface determine the variability of the sputtered-water release and exosphere generation. The so-called planetary space weather conditions around Ganymede can also have a long-term impact on the weathering history of its icy surface.</p> <p>In this talk, I will discuss some key characteristics of the circulation of the Jovian magnetospheric ions within the environment of Ganymede as derived from the application of a single-particle Monte Carlo model driven by the electromagnetic fields from a global MHD model. In particular, the Jovian energetic ion circulation and precipitation to Ganymede’ s surface was estimated for different relative configurations between the moon’s magnetic field and Jupiter’s plasma sheet, characterized by conditions similar to those encountered during the NASA Galileo G2, G8, and G28 flybys of Ganymede (i.e., when the moon was above, inside, and below the center of Jupiter’ s plasma sheet). The resulting differences between the various surface precipitation patterns and the implications in the water sputtering rate will be discussed. The results of this preliminary analysis are relevant to ESA’ s JUICE mission and in particular to the planning of future observation strategies for studying Ganymede’ s environment.</p>

scholarly journals Gold Nanoparticle DNA Damage by Photon Beam in a Magnetic Field: A Monte Carlo Study

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1751
Author(s):  
Mehwish Jabeen ◽  
James C. L. Chow
Keyword(s):  
Magnetic Field ◽  
Dna Damage ◽  
Monte Carlo ◽  
Gold Nanoparticle ◽  
Monte Carlo Model ◽  
Photon Beam ◽  
Dose Enhancement ◽  
The Impact ◽  
The Magnetic Field ◽  
Field Strengths

Ever since the emergence of magnetic resonance (MR)-guided radiotherapy, it is important to investigate the impact of the magnetic field on the dose enhancement in deoxyribonucleic acid (DNA), when gold nanoparticles are used as radiosensitizers during radiotherapy. Gold nanoparticle-enhanced radiotherapy is known to enhance the dose deposition in the DNA, resulting in a double-strand break. In this study, the effects of the magnetic field on the dose enhancement factor (DER) for varying gold nanoparticle sizes, photon beam energies and magnetic field strengths and orientations were investigated using Geant4-DNA Monte Carlo simulations. Using a Monte Carlo model including a single gold nanoparticle with a photon beam source and DNA molecule on the left and right, it is demonstrated that as the gold nanoparticle size increased, the DER increased. However, as the photon beam energy decreased, an increase in the DER was detected. When a magnetic field was added to the simulation model, the DER was found to increase by 2.5–5% as different field strengths (0–2 T) and orientations (x-, y- and z-axis) were used for a 100 nm gold nanoparticle using a 50 keV photon beam. The DNA damage reflected by the DER increased slightly with the presence of the magnetic field. However, variations in the magnetic field strength and orientation did not change the DER significantly.

Interaction of Interplanetary Shocks with the Moon

2020 ◽  
Author(s):  
Xiaoyan Zhou ◽  
Nojan Omidi
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Field Strength ◽  
Shock Front ◽  
Magnetic Field Strength ◽  
Interplanetary Shocks ◽  
The Moon ◽  
Energetic Ions ◽  
The Core ◽  
The Magnetic Field

<p>In this presentation, we use data from THEMIS-ARTEMIS spacecraft and electromagnetic hybrid (kinetic ions, fluid electrons) simulations to describe the nature of the interaction between interplanetary shocks and the Moon. In the absence of a global magnetic field and an ionosphere at the Moon, solar wind interaction is controlled by (1) absorption of the core solar wind protons on the dayside; (2) access of supra-thermal and energetic ions in the solar wind to the lunar tail; (3) penetration and passage of the IMF through the lunar body. This results in a lunar tail populated by energetic ions and enhanced magnetic field in the central tail region. In general, ARTEMIS observations show a clear jump in the magnetic field strength associated with the passage of the interplanetary shock regardless of the position in the tail. Compared to the shock front observed in the solar wind, the magnetic field strength in the tail is stronger both upstream and downstream of the shock which is consistent with the expectations of larger field strengths in the tail. In addition, the transition from upstream to downstream magnetic field strength takes longer time as compared to the solar wind, indicating the broadening in space of the shock transition region. In contrast, plasma observations show that depending on the position of the spacecraft in the tail, a density enhancement in association with the shock front may or may not be observed. Using the observed solar wind conditions, we have used hybrid simulations to examine the interaction of interplanetary shocks with the Moon. The results indicate that by virtue of IMF passage through the lunar body, the magnetic field shock front also passes through the Moon and as such a jump in the magnetic field strength is observed throughout the lunar tail in association with the passage of the shock. As expected, the field strength in the upstream and downstream regions in the tail are larger than the corresponding values in the solar wind. In addition, the passage of the shock through the lunar tail is associated with the broadening of the shock front. The absorption of the core solar wind protons on the dayside introduces a density hole in the shock front as it passes through the Moon and the lunar tail and, as such, the shock front as a whole is disrupted. This hole is gradually filled with the ambient plasma while it travels further down the tail until eventually the shock front is fully restored a few lunar radii away from the Moon. The simulation results are found to be consistent with ARTEMIS observations. Here we also discuss the impacts of shock Mach number on the interaction. These results depict the lunar environment under transient solar wind conditions, which provide helpful information for the NASA’s plan to return humans to the Moon.</p>

scholarly journals Self-consistent Monte Carlo model of particle acceleration by relativistic shocks

2021 ◽  
Vol 2103 (1) ◽  
pp. 012014
Author(s):  
S M Osipov ◽  
A M Bykov ◽  
M Lemoine
Keyword(s):  
Magnetic Field ◽  
Monte Carlo ◽  
Particle Acceleration ◽  
Monte Carlo Model ◽  
Cosmic Ray ◽  
Field Amplification ◽  
Relativistic Shocks ◽  
Self Consistent ◽  
The Magnetic Field ◽  
Accelerated Particles

Abstract We present a self-consistent Monte Carlo model of particle acceleration by relativistic shock waves. The model includes the magnetic field amplification in the shock upstream by cosmic ray driven plasma instabilities. The parameters of the Monte Carlo model are obtained based on PIC calculations. We present the spectra of accelerated particles simulated in the frame of the model.

Monte Carlo calculation of the energy parameters and spatial distribution of the cathodic arc ions while passing through the macro-particles filters

2018 ◽  
Vol 1 (1) ◽  
pp. 30-34 ◽  
Author(s):  
Alexey Chernogor ◽  
Igor Blinkov ◽  
Alexey Volkhonskiy
Keyword(s):  
Magnetic Field ◽  
Mass Transfer ◽  
Monte Carlo ◽  
Monte Carlo Calculation ◽  
Inhomogeneous Magnetic Field ◽  
Flow Energy ◽  
Wide Range ◽  
Field Concentrator ◽  
Cathodic Arc ◽  
The Magnetic Field

The flow, energy distribution and concentrations profiles of Ti ions in cathodic arc are studied by test particle Monte Carlo simulations with considering the mass transfer through the macro-particles filters with inhomogeneous magnetic field. The loss of ions due to their deposition on filter walls was calculated as a function of electric current and number of turns in the coil. The magnetic field concentrator that arises in the bending region of the filters leads to increase the loss of the ions component of cathodic arc. The ions loss up to 80 % of their energy resulted by the paired elastic collisions which correspond to the experimental results. The ion fluxes arriving at the surface of the substrates during planetary rotating of them opposite the evaporators mounted to each other at an angle of 120° characterized by the wide range of mutual overlapping.

Sign in / Sign up

Export Citation Format

Share Document