Entry into outer planet environments. II - Performance of volume reflecting hyperpure silica heat shields

1976 ◽  
Author(s):  
J. HOWE
Keyword(s):  
Outer Planet ◽  
Heat Shields

scholarly journals Elastic Electron Scattering from Methane Molecule in the Energy Range from 50–300 eV

2021 ◽  
Vol 22 (2) ◽  
pp. 647
Author(s):  
Jelena Vukalović ◽  
Jelena B. Maljković ◽  
Karoly Tökési ◽  
Branko Predojević ◽  
Bratislav P. Marinković
Keyword(s):  
Energy Range ◽  
Cross Section ◽  
Cross Sections ◽  
Accurate Determination ◽  
Electron Gun ◽  
Methane Molecule ◽  
Edge Plasma ◽  
Electron Interaction ◽  
Outer Planet ◽  
Elastic Electron

Electron interaction with methane molecule and accurate determination of its elastic cross-section is a demanding task for both experimental and theoretical standpoints and relevant for our better understanding of the processes in Earth’s and Solar outer planet atmospheres, the greenhouse effect or in plasma physics applications like vapor deposition, complex plasma-wall interactions and edge plasma regions of Tokamak. Methane can serve as a test molecule for advancing novel electron-molecule collision theories. We present a combined experimental and theoretical study of the elastic electron differential cross-section from methane molecule, as well as integral and momentum transfer cross-sections in the intermediate energy range (50–300 eV). The experimental setup, based on a crossed beam technique, comprising of an electron gun, a single capillary gas needle and detection system with a channeltron is used in the measurements. The absolute values for cross-sections are obtained by relative-flow method, using argon as a reference. Theoretical results are acquired using two approximations: simple sum of individual atomic cross-sections and the other with molecular effect taken into the account.

scholarly journals Variability in the outer planet aurorae

1992 ◽  
Vol 12 (8) ◽  
pp. 137-148
Author(s):  
John T. Clarke
Keyword(s):  
Outer Planet

Toward constraining Saturn's rotation rate by interior modeling

2021 ◽  
Author(s):  
Nadine Nettelmann ◽  
Jonathan J. Fortney
Keyword(s):  
Broad Spectrum ◽  
Rotation Rate ◽  
Rotation Period ◽  
Outer Planet ◽  
Fall Meeting ◽  
Density Profiles ◽  
A Value ◽  
Periodic Signals ◽  
Under Construction ◽  
Even Harmonics

<p>The rotation rate of the outer planet Saturn is not well constrained by classical measurements of periodic signals [1]. Recent and diverse approaches using a broad spectrum of Cassini and other observational data related to shape, winds, and oscillations are converging toward a value about 6 to 7 minutes faster than the Voyager rotation period.<br>Here we present our method of using zonal wind data and the even harmonics J<sub>2</sub> to J<sub>10</sub> measured during the Cassini Grand Finale tour [2] to infer the deep rotation rate of Saturn. We assume differential rotation on cylinders and generate adiabatic density profiles that match the low-order J<sub>2</sub> and J<sub>4</sub><br>values. Theory of Figures to 7th order is applied to estimate the differences in the high-order moments J<sub>6 </sub>to J<sub>10</sub> that may result from the winds and the assumed reference rotation rate. Presented results are preliminary as the method is under construction [3].</p><p>[1] Fortney, Helled, Nettelmann et al, in: 'Saturn in the 21st century', Cambridge U Press (2018)<br>[2] Iess, Militzer, Kaspi, Science 364:2965 (2019)<br>[3] Nettelmann, AGU Fall Meeting, P066-0007 (2020)</p><p> </p>

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