scholarly journals Gravity and zonal flows of giant planets: From the Euler equation to the thermal wind equation

2017 ◽  
Vol 122 (4) ◽  
pp. 686-700 ◽  
Author(s):  
Hao Cao ◽  
David J. Stevenson
Keyword(s):  
Euler Equation ◽  
Giant Planets ◽  
Zonal Flows ◽  
Thermal Wind

Synergized magnetic and gravity measurements probe the detailed structure of the gas giants' deep atmospheres

2020 ◽  
Author(s):  
Eli Galanti ◽  
Yohai Kaspi
Keyword(s):  
Magnetic Field ◽  
Field Measurements ◽  
Giant Planets ◽  
Flow Profile ◽  
Zonal Flows ◽  
Secular Variations ◽  
Gravity Measurements ◽  
Decay Profile ◽  
The Magnetic Field ◽  
Decay Form

<p>The strong zonal flows observed at the cloud-level of the gas giants extend thousands of kilometers deep into the planetary interior, as indicated by the Juno and Cassini gravity measurements. However, the gravity measurements alone, which are by definition an integrative measure of mass, cannot constrain with high certainty the detailed vertical structure of the flow below the cloud-level. Here we show that taking into account the recent magnetic field measurements of Saturn and past secular variations of Jupiter's magnetic field, give an additional physical constraint on the vertical decay profile of the observed zonal flows in these planets. In Saturn, we find that the cloud-level winds extend into the planet with very little decay (barotropically) down to a depth of around 7,000 km, and then decay rapidly, so that within the next 1,000 km their value reduces to about 1% of that at the cloud-level. This optimal deep flow profile structure of Saturn matches simultaneously both the gravity field and the high-order latitudinal variations in the magnetic field discovered by the recent measurements. In the Jupiter case, using the recent findings indicating the flows in the planet semiconducting region are order centimeters per second, we show that with such a constraint, a flow structure similar to the Saturnian one is consistent with the Juno gravity measurements. Here the winds extend unaltered from the cloud-level to a depth of around 2,000 km and then decay rapidly within the next 600 km to values of around 1%. Thus, in both giant planets, we find that the observed winds  extend unaltered (baroctropically) down to the semiconducting region, and then decay abruptly. While is it plausible that the interaction with the magnetic field in the semiconducting region is responsible for winds final decay, it is yet to be understood whether another mechanism is involved in the process, especially in the initial decay form the strong 10s meter per seconds winds.</p>

Simulating vortices and jets in deep atmospheres of gas giant planets

2020 ◽  
Author(s):  
Rakesh Yadav ◽  
Jeremy Bloxham ◽  
Moritz Heimpel
Keyword(s):  
Giant Planets ◽  
Self Organization ◽  
Surface Dynamics ◽  
Spherical Shells ◽  
Zonal Flows ◽  
Rich Picture ◽  
The Third ◽  
First Case ◽  
Dynamical Features ◽  
Over Time

<p>Decades of observations have painted a dynamic and rich picture of the atmosphere on Saturn and Jupiter. Both planets have a dominant prograde equatorial jet, and strong zonal flows that alternate in direction at higher latitudes, with Saturn also having a mysterious hexagon shape embedded in one of the polar jets. Both planets also have numerous vortices or storms of different sizes scattered on their surface. All these features are striking examples of turbulent self-organization. While observations abound, the physics behind the formation of these dynamical features is still uncertain. Two interpretations have emerged over time: In one, the surface features are shallow, extending to depths ranging from 10s to 100s of kilometers, while, in the other, they extend to 1000s of kilometers. Here we utilize the deep interpretation and investigate the properties of rotating convection in deep spherical shells. We present three cases: In the first case a giant polar cyclone, alternating zonal flows, and a high latitude eastward jet having polygonal patterns form simultaneously; The second case generates alternating zonal flows as well as numerous cyclones and anticyclones on various latitudes; And, the third case exclusively generates anticyclones with few being as large as Jupiter's great red spot. We discuss what drives these features in these turbulent simulations, and what can we learn from these cases about the interior and surface dynamics of Saturn and Jupiter. </p>

scholarly journals Deep rotating convection generates the polar hexagon on Saturn

2020 ◽  
Vol 117 (25) ◽  
pp. 13991-13996 ◽  
Author(s):  
Rakesh K. Yadav ◽  
Jeremy Bloxham
Keyword(s):  
Flow Pattern ◽  
High Latitude ◽  
Large Scale ◽  
Three Dimensional ◽  
Giant Planets ◽  
Zonal Flows ◽  
Self Organized ◽  
Consistent Model ◽  
Self Consistent ◽  
Polygonal Pattern

Numerous land- and space-based observations have established that Saturn has a persistent hexagonal flow pattern near its north pole. While observations abound, the physics behind its formation is still uncertain. Although several phenomenological models have been able to reproduce this feature, a self-consistent model for how such a large-scale polygonal jet forms in the highly turbulent atmosphere of Saturn is lacking. Here, we present a three-dimensional (3D) fully nonlinear anelastic simulation of deep thermal convection in the outer layers of gas giant planets that spontaneously generates giant polar cyclones, fierce alternating zonal flows, and a high-latitude eastward jet with a polygonal pattern. The analysis of the simulation suggests that self-organized turbulence in the form of giant vortices pinches the eastward jet, forming polygonal shapes. We argue that a similar mechanism is responsible for exciting Saturn’s hexagonal flow pattern.

Synergized magnetic and gravity measurements probe the detailed structure of the gas giants' deep atmospheres

2020 ◽  
Author(s):  
Eli Galanti ◽  
Yohai Kaspi
Keyword(s):  
Magnetic Field ◽  
Field Measurements ◽  
Giant Planets ◽  
Flow Profile ◽  
Zonal Flows ◽  
Secular Variations ◽  
Gravity Measurements ◽  
Decay Profile ◽  
The Magnetic Field ◽  
Decay Form

<p>The strong zonal flows observed at the cloud-level of the gas giants extend thousands of kilometers deep into the planetary interior, as indicated by the Juno and Cassini gravity measurements. However, the gravity measurements alone, which are by definition an integrative measure of mass, cannot constrain with high certainty the detailed vertical structure of the flow below the cloud-level. Here we show that taking into account the recent magnetic field measurements of Saturn and past secular variations of Jupiter's magnetic field, give an additional physical constraint on the vertical decay profile of the observed zonal flows in these planets. In Saturn, we find that the cloud-level winds extend into the planet with very little decay (barotropically) down to a depth of around 7,000 km, and then decay rapidly, so that within the next 1,000 km their value reduces to about 1% of that at the cloud-level. This optimal deep flow profile structure of Saturn matches simultaneously both the gravity field and the high-order latitudinal variations in the magnetic field discovered by the recent measurements. In the Jupiter case, using the recent findings indicating the flows in the planet semiconducting region are order centimeters per second, we show that with such a constraint, a flow structure similar to the Saturnian one is consistent with the Juno gravity measurements. Here the winds extend unaltered from the cloud-level to a depth of around 2,000 km and then decay rapidly within the next 600 km to values of around 1%. Thus, in both giant planets, we find that the observed winds  extend unaltered (baroctropically) down to the semiconducting region, and then decay abruptly. While it is plausible that the interaction with the magnetic field in the semiconducting region is responsible for winds final decay, it is yet to be understood whether another mechanism is involved in the process, especially in the initial decay form the strong 10s meter per seconds winds.</p>

Universal n−5 spectrum of zonal flows on giant planets

2001 ◽  
Vol 13 (6) ◽  
pp. 1545-1548 ◽  
Author(s):  
Boris Galperin ◽  
Semion Sukoriansky ◽  
Huei-Ping Huang
Keyword(s):  
Giant Planets ◽  
Zonal Flows

scholarly journals Combined magnetic and gravity measurements probe the deep zonal flows of the gas giants

2021 ◽  
Author(s):  
Eli Galanti ◽  
Yohai Kaspi
Keyword(s):  
Magnetic Field ◽  
Field Measurements ◽  
Giant Planets ◽  
Flow Profile ◽  
Zonal Flows ◽  
Secular Variations ◽  
Gravity Measurements ◽  
Decay Profile ◽  
The Magnetic Field ◽  
Decay Form

<p>The strong zonal flows observed at the cloud-level of the gas giants extend thousands of kilometers deep into the planetary interior, as indicated by the Juno and Cassini gravity measurements. However, the gravity measurements alone, which are by definition an integrative measure of mass, cannot constrain with high certainty the detailed vertical structure of the flow below the cloud-level. Here we show that taking into account the recent magnetic field measurements of Saturn and past secular variations of Jupiter's magnetic field, give an additional physical constraint on the vertical decay profile of the observed zonal flows in these planets. In Saturn, we find that the cloud-level winds extend into the planet with very little decay (barotropically) down to a depth of around 7,000 km, and then decay rapidly, so that within the next 1,000 km their value reduces to about 1% of that at the cloud-level. This optimal deep flow profile structure of Saturn matches simultaneously both the gravity field and the high-order latitudinal variations in the magnetic field discovered by the recent measurements. In the Jupiter case, using the recent findings indicating the flows in the planet semiconducting region are order centimeters per second, we show that with such a constraint, a flow structure similar to the Saturnian one is consistent with the Juno gravity measurements. Here the winds extend unaltered from the cloud-level to a depth of around 2,000 km and then decay rapidly within the next 600 km to values of around 1%. Thus, in both giant planets, we find that the observed winds  extend unaltered (baroctropically) down to the semiconducting region, and then decay abruptly. While it is plausible that the interaction with the magnetic field in the semiconducting region is responsible for winds final decay, it is yet to be understood whether another mechanism is involved in the process, especially in the initial decay form the strong 10s meter per seconds winds.</p>

scholarly journals Reversal and amplification of zonal flows by boundary enforced thermal wind

Icarus ◽  
2017 ◽  
Vol 282 ◽  
pp. 380-392 ◽  
Author(s):  
W. Dietrich ◽  
T. Gastine ◽  
J. Wicht
Keyword(s):  
Zonal Flows ◽  
Thermal Wind
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