MHD simulation of a rapidly rotating magnetosphere interacting with the external plasma flow

Miyoshi, Tetsuya; Kusano, K.

doi:10.1029/97gl52739

Cited by 15 publications

(10 citation statements)

References 18 publications

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“…In the predawn sector of the Jovian magnetosphere the flow appears to be episodically enhanced with respect to corotation. This behavior is in qualitative agreement with steady state MHD simulations where this enhancement is also present [Miyoshi and Kusano, 1997]. Such a superrotation of particles has been indirectly suggested from evidence of a forward spiral of magnetic field lines crossing the equatorial plasma sheet in the predawn magnetosphere on the Voyager 1 and 2 outbound segments [Hairston and Hill, 1986].…”

Section: Discussionsupporting

confidence: 84%

See 1 more Smart Citation

Global flows of energetic ions in Jupiter's equatorial plane: First‐order approximation

Krupp¹,

Lagg²,

Livi³

et al. 2001

J. Geophys. Res.

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Galileo, as the first orbiting spacecraft in an outer planet's magnetosphere, provides the opportunity to study global energetic ion distributions in Jupiter's magnetosphere. We present directional anisotropies of energetic ion distributions measured by the Galileo Energetic Particles Detector (EPD). The EPD measurements of proton (80–1050 keV), oxygen (26–562 keV/nucleon), and sulfur (16–310 keV/nucleon) distributions cover a wide energy range. Spatially, the data set includes measurements from 6 to 142 Jovian radii (RJ) and covers all local times inside the Jovian magnetosphere. For each species a single detector head scans almost the entire sky (≈ 4π sr), producing the three‐dimensional angular distributions from which the anisotropies are derived. Consequently, the resulting anisotropy estimates are both global and robust. Such anisotropies, generally produced by convective flow, ion intensity gradients, and field‐aligned components, have long been used to estimate flow velocities and to locate spatial boundaries within magnetospheres. They can therefore provide vital information on magnetospheric circulation and dynamics. We find that the EPD measured anisotropies in the Jovian magnetosphere are dominated by a component in the corotational direction punctuated by episodic radial components, both inward and outward. Under the assumption that anisotropies are produced predominantly by convective flow, we derive flow velocities of protons, oxygen ions, and sulfur ions. The validity of that approach is supported by the fact that these three independently derived flow velocities agree, to a large extent, in this approximation. Thus, for the first time, we are able to derive the global flow pattern in a magnetosphere of an outer planet. In a comparison between the first‐order EPD flow velocities and those predicted by a magnetohydrodynamic (MHD) simulation of the Jovian magnetosphere, we find that qualitatively the directions appear similar, although no firm evidence of steady outflow of ions has been observed at distances covered by Galileo. A first rough comparison indicates that the measured first‐order flow velocities are higher by at least a factor of 1.5 than the MHD simulation results.

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Section: Discussionsupporting

confidence: 84%

“…Measurements presented here could not confirm a steady outflow of particles in the midtail around 140 Ra as predicted by the simulations of Ogino et al [ 1998] and Miyoshi and Kusano [1997]. The steady state global flow pattern (without the particle bursts discussed above) indicates that corotation dominates out to at least 142 Ra.…”

Section: Discussioncontrasting

confidence: 77%

Global flows of energetic ions in Jupiter's equatorial plane: First‐order approximation

Krupp¹,

Lagg²,

Livi³

et al. 2001

J. Geophys. Res.

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“…In addition, the Io torus is located at 10 R J , instead of 5.9 R J because we want to have a clear separation between the Io torus and the ionospheric region. Note that in other global simulations of Jupiter's magnetosphere, the inner boundary is located farther away: between 8 R J in Moriguchi et al [] and 30 R J in Miyoshi and Kusano [] and that the Io torus is not included.…”

Section: Physical Setup and Numerical Modelmentioning

confidence: 99%

How is the Jovian main auroral emission affected by the solar wind?

et al. 2017

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The influence of the solar wind on Jupiter's magnetosphere is studied via three‐dimensional global MHD simulations. We especially examine how solar wind density variations affect the main auroral emission. Our simulations show that a density increase in the solar wind has strong effects on the Jovian magnetosphere: the size of the magnetosphere decreases, the field lines are compressed on the dayside and elongated on the nightside (this effect can be seen even deep inside the magnetosphere), and dawn‐dusk asymmetries are enhanced. Our results also show that the main oval becomes brighter when the solar wind is denser. But the precise response of the main oval to such a density enhancement in the solar wind depends on the local time: on the nightside the main oval becomes brighter, while on the dayside it first turns slightly darker for a few hours and then also becomes brighter. Once the density increase in the solar wind reaches the magnetosphere, the magnetopause moves inward, and in less than 5 h, a new approximate equilibrium position is obtained. But the magnetosphere as a whole needs much longer to adapt to the new solar wind conditions. For instance, the total electrical current closing in the ionosphere slowly increases during the simulation and it takes about 60 h to reach a new equilibrium. By then the currents have increased by as much as 45%.

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“…In the early days, the effects of the ionosphere and the Io plasma source were not seriously considered. For example, the locations of the inner boundary were set far away from the planetary surface: 30R J (1R J = 71492 km, the radius of Jupiter) in Miyoshi and Kusano (1997), Miyoshi and Kusano (2001), 21R J in Ogino et al (1998), Walker et al (2001 and Fukazawa et al (2005). In these models, the plasma source and the ionosphere were not included.…”

Section: Introductionmentioning

confidence: 99%

Modeling the Jovian magnetosphere under an antiparallel interplanetary magnetic field from a global MHD simulation

Wang

Guo

Tang

et al. 2018

Earth and Planetary Physics

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We present preliminary results of a new global Magnetohydrodynamics (MHD) simulation model of the Jovian magnetosphere. The model incorporates mass loading from Jupiter's satellite Io, the planet's fast corotation, and electrostatic coupling between its magnetosphere and ionosphere (M‐I coupling). The basic configuration of the Jovian magnetosphere including the equatorial plasma flow pattern, the corotation enforcement current system, and the field aligned currents (FACs) in the ionosphere are presented under an antiparallel interplanetary magnetic field (IMF) condition. The simulation model results for equatorial density and pressure profiles are consistent with results from data‐based empirical models. It is also found that there are similarities between the FACs distribution in the ionosphere and the observed aurora features, showing the potential application of the simple ionospheric model to the complicated M‐I coupling. This model will help deepen our understanding of the global dynamics of the Jovian magnetosphere.

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MHD simulation of a rapidly rotating magnetosphere interacting with the external plasma flow

Cited by 15 publications

References 18 publications

Global flows of energetic ions in Jupiter's equatorial plane: First‐order approximation

Global flows of energetic ions in Jupiter's equatorial plane: First‐order approximation

How is the Jovian main auroral emission affected by the solar wind?

Modeling the Jovian magnetosphere under an antiparallel interplanetary magnetic field from a global MHD simulation

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