Interplay of bubble injections in the plasma sheet dynamics as inferred from RCM-I simulations

2020 ◽  
Author(s):  
Sina Sadeghzadeh ◽  
Jian Yang
Keyword(s):  
Plasma Sheet ◽  
High Speed ◽  
Space Environment ◽  
Inner Magnetosphere ◽  
Near Earth Space ◽  
Hot Plasma ◽  
Plasma Distribution ◽  
Rice Convection Model ◽  
Convection Model ◽  
Interchange Instability

<p><span>Understanding the transport of hot plasma from tail towards the inner magnetosphere is of great importance to improve our perception of the near-Earth space environment. In accordance with the recent observations, the contribution of bursty bulk flows (BBFs)/bubbles in the inner plasma sheet especially in the storm-time ring current formation is nonnegligible. These high-speed plasma flows with depleted flux tube/entropy are likely formed in the mid tail due to magnetic reconnection and injected earthward as a result of interchange instability. In this presentation, we investigate the interplay of these meso-scale structures on the average magnetic field and plasma distribution in various regions of the plasma sheet, using the Inertialized Rice Convection Model (RCM-I). We will discuss the comparison of our simulation results with the observational statistics and data-based empirical models.</span></p>

Aluminum Shield Under Hypervelocity Impact of Mylar Flyer

2008 ◽  
Author(s):  
J. Zhao ◽  
F. Tan ◽  
C. Liu ◽  
C. Sun
Keyword(s):  
High Speed ◽  
Hypervelocity Impact ◽  
Space Environment ◽  
Lateral Expansion ◽  
Near Earth Space ◽  
The Third ◽  
Naturally Occurring ◽  
Debris Cloud ◽  
The Impact ◽  
Different Thickness

The near-earth space environment is cluttered with man-made debris and naturally occurring meteoroids, which is a big menace to the safety of satellites and spacecrafts. This paper is addressed on the failure response of aluminum shields under hypervelocity impact of milligrame level flyer. A compacted electric gun is employed to accelerate a mylar flyer up to 10 km/s. Failure response of Ly12 aluminum shields with different thickness and layers impacted by mylar flyer with different velocities is under investigation. The spallation is observed in the rear free surface of 4 mm thick monolithic aluminum shield, and its fracture mechanism changes from plastic to brittle when loading pressure is above 13 GPa. A perforation with a diameter 8 mm in the impacted area of the 4mm thick Ly12 shield is observed after which is impacted by 0.1 mm thick mylar flyer 8mm in diameter with velocity 8.2 km/s. When three layers of shields are impacted, the debris clouds (DC) are observed in the first and the second spaces respectively during the impact process by high speed camera, and its leftover can be observed on the surface of the third plate. The shape of the first debris cloud head is a little flat, and its speed of lateral expansion is very slow, which is different from those impacted by spherical projectile, and its formation mechanics mainly attributes to multi-spallations based on the analysis of simulation.

Rice Convection Model simulation of the 18 April 2002 sawtooth event and evidence for interchange instability

2008 ◽  
Vol 113 (A11) ◽  
pp. n/a-n/a ◽  
Author(s):  
J. Yang ◽  
F. R. Toffoletto ◽  
R. A. Wolf ◽  
S. Sazykin ◽  
R. W. Spiro ◽  
...  
Keyword(s):  
Model Simulation ◽  
Rice Convection Model ◽  
Convection Model ◽  
Interchange Instability

Numerical simulation of plasma transport in Saturn's inner magnetosphere using the Rice Convection Model

2010 ◽  
Vol 115 (A12) ◽  
pp. n/a-n/a ◽  
Author(s):  
X. Liu ◽  
T. W. Hill ◽  
R. A. Wolf ◽  
S. Sazykin ◽  
R. W. Spiro ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Plasma Transport ◽  
Inner Magnetosphere ◽  
Rice Convection Model ◽  
Convection Model

scholarly journals Numerical considerations in simulating the global magnetosphere

2010 ◽  
Vol 28 (8) ◽  
pp. 1589-1614 ◽  
Author(s):  
A. J. Ridley ◽  
T. I. Gombosi ◽  
I. V. Sokolov ◽  
G. Tóth ◽  
D. T. Welling
Keyword(s):  
Grid Resolution ◽  
Mhd Equations ◽  
Space Environment ◽  
Speed Of Light ◽  
Numerical Schemes ◽  
Inner Magnetosphere ◽  
Near Earth Space ◽  
Computational Resources ◽  
The University ◽  
Density Boundary

Abstract. Magnetohydrodynamic (MHD) models of the global magnetosphere are very good research tools for investigating the topology and dynamics of the near-Earth space environment. While these models have obvious limitations in regions that are not well described by the MHD equations, they can typically be used (or are used) to investigate the majority of magnetosphere. Often, a secondary consideration is overlooked by researchers when utilizing global models – the effects of solving the MHD equations on a grid, instead of analytically. Any discretization unavoidably introduces numerical artifacts that affect the solution to various degrees. This paper investigates some of the consequences of the numerical schemes and grids that are used to solve the MHD equations in the global magnetosphere. Specifically, the University of Michigan's MHD code is used to investigate the role of grid resolution, numerical schemes, limiters, inner magnetospheric density boundary conditions, and the artificial lowering of the speed of light on the strength of the ionospheric cross polar cap potential and the build up of the ring current in the inner magnetosphere. It is concluded that even with a very good solver and the highest affordable grid resolution, the inner magnetosphere is not grid converged. Artificially reducing the speed of light reduces the numerical diffusion that helps to achieve better agreement with data. It is further concluded that many numerical effects work nonlinearly to complicate the interpretation of the physics within the magnetosphere, and so simulation results should be scrutinized very carefully before a physical interpretation of the results is made. Our conclusions are not limited to the Michigan MHD code, but apply to all MHD models due to the limitations of computational resources.

Bimodal Plasma Sheet Flow

1996 ◽  
Author(s):  
Charles F. Kennel
Keyword(s):  
Solar Wind ◽  
Steady Flow ◽  
Plasma Sheet ◽  
High Speed ◽  
Large Data ◽  
Field Configuration ◽  
Data Sets ◽  
Sheet Flow ◽  
Convection Model ◽  
Steady Convection

How does the plasma sheet respond to the complex pattern of waves coming over the poles from bursty magnetopause reconnection events, or to the vortices and other irregular perturbations coming around the flanks of the magnetosphere in the low-latitude boundary layer? It is probably too much to expect that the complex input from the dayside will sort itself out into a steady flow on the nightside, but there has been a seductive hope that, on a statistical basis, the observations of the plasma sheet could be rationalized using steady convection thinking. This hope depends on the belief that the average magnetic field configuration in the plasma sheet actually is compatible with steady convection. The first doubts on this score were raised by Erickson and Wolf (1980), and were subsequently elaborated by Tsyganenko (1982), Birn and Schindler (1983), and Liu and Hill (1985); the“plasma sheet pressure paradox” they posed is the subject of Section 9.2. Theoretical arguments are one thing, measurements are another; the truly important issue is whether the real plasma sheet manifests steady flow. Several groups have searched large data sets to see whether the statistically averaged flow in the central plasma sheet resembles the flow predicted by the steady convection model. This effort has led to a growing but still incomplete comprehension of the statistical properties of plasma sheet transport. Results obtained using ensembles of data acquired by ISEE 1 and AMPTE/IRM will be reviewed in Section 9.3. The unusual distribution of bulk flow velocities suggests that the plasma sheet flow is bimodal, alternating between a predominant irregular low-speed state and an infrequently occurring state of high-speed earthward flow. In search of steady plasma sheet flow, one could also look into substormfree periods of stable solar wind properties. One of the best such studies, in which great care was taken to find periods of exceptionally stable solar wind and geomagnetic conditions, is reviewed in Section 9.4. Even this study found highly irregular and bursty flow.

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