A preliminary study of Magnetosphere-Ionosphere-Thermosphere coupling key parameters at Jupiter Based on Juno multi-instrument data and modelling tools

2020 ◽  
Author(s):  
Michel Blanc ◽  
Yuxian Wang ◽  
Nicolas Andre ◽  
Pierre-Louis Blelly ◽  
Corentin Louis ◽  
...  
Keyword(s):  
Electric Fields ◽  
Plasma Source ◽  
Neutral Atmosphere ◽  
Solar Wind Interaction ◽  
Jovian Magnetosphere ◽  
Use Of Data ◽  
Field Lines ◽  
Auroral Emissions ◽  
Coupling Processes

<p>The dynamics of the Jovian magnetosphere is controlled by the complex interplay of the planet’s fast rotation, its solar-wind interaction and its main plasma source at the Io torus. Juno observations have amply demonstrated that the Magnetosphere-Ionosphere-Thermosphere (MIT) coupling processes and regimes which control this interplay are significantly different from their Earth and Saturn counterparts. At the ionospheric level, these MIT coupling processes can be characterized by a set of key parameters which include ionospheric electrodynamic parameters (conductances, currents and electric fields), exchanges of particles along field lines and auroral emissions. Knowledge of these key parameters in turn makes it possible to estimate the net deposition/extraction of momentum and energy into/out of the Jovian upper atmosphere. We will present a method combining Juno multi-instrument data (MAG, JADE, JEDI, UVS, JIRAM and WAVES), adequate modelling tools (the TRANSPLANET ionospheric dynamics model and a simplified set of ionospheric current closure equations) and the AMDA data handling tools to provide preliminary estimates of these key parameters and their variation along the ionospheric footprint of Juno’s magnetic field line and across the auroral ovals for three of the first perijoves of the mission. We will discuss how this synergistic use of data and models can also contribute to provide a better determination of poorly known parameters such as the vertical structure of the auroral and polar Jovian neutral atmosphere.</p> <p> </p>

scholarly journals Magnetosphere-Ionosphere-Thermosphere Coupling study at Jupiter Based on Juno First 30 Orbits and Modelling Tools

2021 ◽  
Author(s):  
Sariah Al Saati ◽  
Noé Clément ◽  
Michel Blanc ◽  
Yuxian Wang ◽  
Nicolas André ◽  
...  
Keyword(s):  
Electric Fields ◽  
Plasma Source ◽  
Solar Wind Interaction ◽  
The North ◽  
Jovian Magnetosphere ◽  
Model Predictions ◽  
Field Lines ◽  
Auroral Emissions ◽  
Coupling Processes ◽  
North And South

<p class="western" lang="en-US" align="justify">The dynamics of the Jovian magnetosphere is controlled by the complex interplay of the planet’s fast rotation, its solar-wind interaction and its main plasma source at the Io torus. At the ionospheric level, these MIT coupling processes can be characterized by a set of key parameters which include ionospheric conductances, currents and electric fields, exchanges of particles along field lines and auroral emissions. Knowledge of these key parameters in turn makes it possible to estimate the net deposition/extraction of momentum and energy into/out of the Jovian upper atmosphere. In this talk we will extend to the first thirty Juno science orbits the method described in Wang et al. (JGR 2021, under review) which combines Juno multi-instrument data (MAG, JADE, JEDI, UVS, JIRAM and WAVES), adequate modelling tools and data bases to retrieve these key parameters along the Juno magnetic footprint and across the north and south auroral ovals. We will present preliminary distributions of conductances, electric currents and electric fields obtained from these orbits and will compare them with model predictions.</p>

Magnetosphere-Ionosphere-Thermosphere Coupling study at Saturn Based on Cassini high-latitude and Grand Finale Orbits and Modelling Tools

2021 ◽  
Author(s):  
Noé Clément ◽  
Sariah Al Saati ◽  
Michel Blanc ◽  
Yuxian Wang ◽  
Nicolas André ◽  
...  
Keyword(s):  
Electric Fields ◽  
Solar Wind Interaction ◽  
Plasma Sources ◽  
The North ◽  
Model Predictions ◽  
Field Lines ◽  
Auroral Emissions ◽  
F Ring ◽  
Coupling Processes ◽  
North And South

<p class="western" lang="en-US" align="justify">The dynamics of the Kronian magnetosphere is controlled by the complex interplay of the planet’s fast rotation, its solar-wind interaction and its main plasma sources at Enceladus and other moons. At the ionospheric level, these MIT coupling processes can be characterized by a set of key parameters which include ionospheric conductances, currents and electric fields, exchanges of particles along field lines and auroral emissions. Knowledge of these key parameters in turn makes it possible to estimate the net deposition/extraction of momentum and energy into/out of the Kronian upper atmosphere. In this talk we will apply to Cassini high-inclination, F-ring and Grand Finale orbits the method developed and tested by Wang et al. (JGR 2021, under review) for Juno studies. We will combine Cassini multi-instrument data (MAG, CAPS, MIMI, UVIS and RPWS) with adequate modelling tools and data bases to retrieve these key parameters along the Cassini magnetic footprint and across the north and south auroral ovals. We will present preliminary distributions of conductances, electric currents and electric fields obtained from these orbits and will compare them with model predictions.</p>

scholarly journals Transpolar aurora: time evolution, associated convection patterns, and a possible cause

2005 ◽  
Vol 23 (5) ◽  
pp. 1917-1930 ◽  
Author(s):  
L. G. Blomberg ◽  
J. A. Cumnock ◽  
I. I. Alexeev ◽  
E. S. Belenkaya ◽  
S. Yu. Bobrovnikov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electric Fields ◽  
Auroral Oval ◽  
Plasma Convection ◽  
Ionosphere Plasma ◽  
Auroral Electrons ◽  
Field Lines ◽  
Convection Patterns ◽  
Auroral Emissions ◽  
Set Up

Abstract. We present two event studies illustrating the detailed relationships between plasma convection, field-aligned currents, and polar auroral emissions, as well as illustrating the influence of the Interplanetary Magnetic Field's y-component on theta aurora development. The transpolar arc of the theta aurorae moves across the entire polar region and becomes part of the opposite side of the auroral oval. Electric and magnetic field and precipitating particle data are provided by DMSP, while the POLAR UVI instrument provides measurements of auroral emissions. Ionospheric electrostatic potential patterns are calculated at different times during the evolution of the theta aurora using the KTH model. These model patterns are compared to the convection predicted by mapping the magnetopause electric field to the ionosphere using the Paraboloid Model of the magnetosphere. The model predicts that parallel electric fields are set up along the magnetic field lines projecting to the transpolar aurora. Their possible role in the acceleration of the auroral electrons is discussed. Keywords. Ionosphere (Plasma convection; Polar ionosphere) – Magnetospheric physics (Magnetosphereionosphere interactions)

scholarly journals A model of the plasma flow and current in Saturn's polar ionosphere under conditions of strong Dungey cycle driving

2006 ◽  
Vol 24 (3) ◽  
pp. 1029-1055 ◽  
Author(s):  
C. M. Jackman ◽  
S. W. H. Cowley
Keyword(s):  
Flow Pattern ◽  
Hubble Space Telescope ◽  
Plasma Source ◽  
Closed Field ◽  
Current Layer ◽  
Polar Ionosphere ◽  
Solar Wind Interaction ◽  
Outer Magnetosphere ◽  
Field Aligned Current ◽  
Field Lines

Abstract. We propose a simple model of the flow and currents in Saturn's polar ionosphere. This model is motivated by theoretical reasoning, and guided quantitatively by in situ field and flow data from space missions, ground-based IR Doppler measurements, and Hubble Space Telescope images. The flow pattern consists of components which represent (1) plasma sub-corotation in the middle magnetosphere region resulting from plasma pick-up and radial transport from internal sources; (2) the Vasyliunas-cycle of internal plasma mass-loss down the magnetospheric tail at higher latitudes; and (3) the polar Dungey-cycle flow driven by the solar wind interaction. Upstream measurements of the interplanetary magnetic field (IMF) indicate the occurrence of both extended low-field rarefaction intervals with essentially negligible Dungey-cycle flow, and few-day high-field compression regions in which the Dungey-cycle voltage peaks at a few hundred kV. Here we model the latter conditions when the Dungey-cycle is active, advancing on previous axi-symmetric models which may be more directly applicable to quiet conditions. For theoretical convenience the overall flow pattern is constructed by adding together two components - a purely rotational flow similar to previous axi-symmetric models, and a sun-aligned twin vortex representing the dawn-dusk asymmetry effects associated with the Vasyliunas-and Dungey-cycle flows. We calculate the horizontal ionospheric current associated with the flow and the field-aligned current from its divergence. These calculations show that a sheet of upward-directed field-aligned current flows at the boundary of open field lines which is strongly modulated in local-time by the Dungey-cycle flows. We then consider implications of the field-aligned current for magnetospheric electron acceleration and aurorae using two plasma source populations (hot outer magnetospheric electrons and cool dense magnetosheath electrons). Both sources display a strong dawn-dusk asymmetry in the accelerating voltages required and the energy fluxes produced, resulting from the corresponding asymmetry in the current. The auroral intensities for the outer magnetosphere source are typically ~50 kR at dawn and ~5 kR at dusk, in conformity with recent auroral observations under appropriate conditions. However, those for the magnetosheath source are much smaller. When the calculated precipitating electron energy flux values are integrated across the current layer and around the open closed field line boundary, this yields total UV output powers of ~10 GW for the hot outer magnetosphere source, which also agrees with observations.

scholarly journals High resolution observations of spectral width features associatedwith ULF wave signatures in artificial HF radar backscatter

2004 ◽  
Vol 22 (1) ◽  
pp. 169-182 ◽  
Author(s):  
D. M. Wright ◽  
T. K. Yeoman ◽  
L. J. Baddeley ◽  
J. A. Davies ◽  
R. S. Dhillon ◽  
...  
Keyword(s):  
High Resolution ◽  
Plasma Source ◽  
Spectral Width ◽  
Hf Radar ◽  
Mhd Waves ◽  
Small Scale ◽  
Ulf Waves ◽  
Source Population ◽  
Radar Backscatter ◽  
Field Lines

Abstract. The EISCAT high power heating facility at Tromsø, northern Norway, has been utilised to generate artificial radar backscatter in the fields of view of the CUTLASS HF radars. It has been demonstrated that this technique offers a means of making very accurate and high resolution observations of naturally occurring ULF waves. During such experiments, the usually narrow radar spectral widths associated with artificial irregularities increase at times when small scale-sized (high m-number) ULF waves are observed. Possible mechanisms by which these particle-driven high-m waves may modify the observed spectral widths have been investigated. The results are found to be consistent with Pc1 (ion-cyclotron) wave activity, causing aliasing of the radar spectra, in agreement with previous modelling work. The observations also support recent suggestions that Pc1 waves may be modulated by the action of longer period ULF standing waves, which are simultaneously detected on the magnetospheric field lines. Drifting ring current protons with energies of ∼ 10keV are indicated as a common plasma source population for both wave types. Key words. Magnetospheric physics (MHD waves and instabilities) – Space plasma physics (wave-particle interactions) – Ionosphere (active experiments)

scholarly journals RF-Carpets that Compress Ions to High Density Beams

2015 ◽  
Vol 21 (S4) ◽  
pp. 84-89
Author(s):  
H. Wollnik ◽  
F. Arai ◽  
Y. Ito ◽  
P. Schury ◽  
M. Wada
Keyword(s):  
Phase Space ◽  
Electric Field ◽  
Electric Fields ◽  
Ion Beams ◽  
High Density ◽  
Ion Density ◽  
Field Lines

AbstractIons that are moved by electric fields in gases follow quite exactly the electric field lines since these ions have substantially lost their kinetic energies in collisions with gas atoms or molecules and so carry no momenta. Shaping the electric fields appropriately the phase space such ion beams occupy can be reduced and correspondingly the ion density of beams be increased.

scholarly journals Mapping of steady-state electric fields and convective drifts in geomagnetic fields – Part 1: Elementary models

2016 ◽  
Vol 34 (1) ◽  
pp. 55-65 ◽  
Author(s):  
A. D. M. Walker ◽  
G. J. Sofko
Keyword(s):  
Magnetic Field ◽  
Steady State ◽  
Electric Field ◽  
Electric Fields ◽  
Magnetic Field Line ◽  
Geomagnetic Field ◽  
Geomagnetic Field Models ◽  
Spatial Derivatives ◽  
Field Lines ◽  
The Magnetic Field

Abstract. When studying magnetospheric convection, it is often necessary to map the steady-state electric field, measured at some point on a magnetic field line, to a magnetically conjugate point in the other hemisphere, or the equatorial plane, or at the position of a satellite. Such mapping is relatively easy in a dipole field although the appropriate formulae are not easily accessible. They are derived and reviewed here with some examples. It is not possible to derive such formulae in more realistic geomagnetic field models. A new method is described in this paper for accurate mapping of electric fields along field lines, which can be used for any field model in which the magnetic field and its spatial derivatives can be computed. From the spatial derivatives of the magnetic field three first order differential equations are derived for the components of the normalized element of separation of two closely spaced field lines. These can be integrated along with the magnetic field tracing equations and Faraday's law used to obtain the electric field as a function of distance measured along the magnetic field line. The method is tested in a simple model consisting of a dipole field plus a magnetotail model. The method is shown to be accurate, convenient, and suitable for use with more realistic geomagnetic field models.

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