More on the expansion of a collisionless plasma into the wake of a body

1986 ◽  
Vol 35 (1) ◽  
pp. 119-123 ◽  
Author(s):  
K. H. Wright ◽  
D. E. Parks ◽  
I. Katz ◽  
N. H. Stone ◽  
U. Samir
Keyword(s):  
Collisionless Plasma ◽  
Quantitative Agreement ◽  
Plasma Expansion ◽  
Laboratory Measurements ◽  
Good Quantitative Agreement ◽  
Expansion Model ◽  
Analytical Expressions ◽  
Insight Into ◽  
Recent Laboratory

Recent laboratory measurements of plasma expansion in a plasma wake experiment are compared with analytical expressions which approximate the plasma expansion model of Crow, Auer & Allen. Good quantitative agreement was found between the data and theory for the velocity and position of the ion expansion front. These results provide an important insight into the behaviour of the expansion early in its development.

Steady streaming within a periodically rotating sphere

2008 ◽  
Vol 608 ◽  
pp. 71-80 ◽  
Author(s):  
RODOLFO REPETTO ◽  
JENNIFER H. SIGGERS ◽  
ALESSANDRO STOCCHINO
Keyword(s):  
Series Expansion ◽  
Oscillation Frequency ◽  
Small Amplitude ◽  
Quantitative Agreement ◽  
Torsional Oscillations ◽  
Rotating Sphere ◽  
Good Quantitative Agreement ◽  
Steady Streaming ◽  
Theory And Experiments ◽  
Streaming Flow

We consider the flow in a spherical chamber undergoing periodic torsional oscillations about an axis through its centre, and analyse it both theoretically and experimentally. We calculate the flow in the limit of small-amplitude oscillations in the form of a series expansion in powers of the amplitude, finding that at second order, a steady streaming flow develops consisting of two toroidal cells. This streaming behaviour is also observed in our experiments. We find good quantitative agreement between theory and experiments, and we discuss the dependence of the steady streaming behaviour as both the oscillation frequency and amplitude are varied.

Grid-based Vlasov simulation of collisionless plasma expansion

2021 ◽  
Vol 28 (9) ◽  
pp. 093510
Author(s):  
Chen Cui ◽  
Joseph Wang
Keyword(s):  
Collisionless Plasma ◽  
Plasma Expansion ◽  
Grid Based

scholarly journals Compressive strength of comet 67P/Churyumov-Gerasimenko derived from Philae surface contacts

2019 ◽  
Vol 630 ◽  
pp. A2 ◽  
Author(s):  
P. Heinisch ◽  
H.-U. Auster ◽  
B. Gundlach ◽  
J. Blum ◽  
C. Güttler ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Surface Material ◽  
Laboratory Measurements ◽  
Camera System ◽  
Upper Limit ◽  
Rosetta Mission ◽  
Ballistic Trajectory ◽  
Comet 67P ◽  
Insight Into ◽  
Impact Probe

Context. The landing and rebound of the Philae lander, which was part of the ESA Rosetta mission, enabled us to study the mechanical properties of the surface of comet 67P/Churyumov-Gerasimenko, because we could use Philae as an impact probe. Aims. The aim is to approximate the descent and rebound trajectory of the Philae lander and use this information to derive the compressive strength of the surface material from the different surface contacts and scratches created during the final touchdown. Combined with laboratory measurements, this can give an insight into what comets are made of and how they formed. Methods. We combined observations from the ROMAP magnetometer on board Philae with observations made by the Rosetta spacecraft, particularly by the OSIRIS camera system and the RPC-MAG magnetometer. Additionally, ballistic trajectory and collision modeling was performed. These results are placed in context using laboratory measurements of the compressibility of different materials. Results. It was possible to reconstruct possible trajectories of Philae and determine that a pressure of ~100 Pa is enough to compress the surface material up to a depth of ~20 cm. Considering all errors, the derived compressive strength shows little dependence on location, with an overall upper limit for the surface compressive strength of ~800 Pa.

scholarly journals Comments on the generation mechanism of Seismic Electric Signals

2011 ◽  
Vol 11 (12) ◽  
pp. 3093-3096 ◽  
Author(s):  
E. Dologlou
Keyword(s):  
Power Law ◽  
Thermodynamic Model ◽  
Stress Drop ◽  
Lead Time ◽  
Generation Mechanism ◽  
Laboratory Measurements ◽  
Bulk Properties ◽  
Seismic Electric Signals ◽  
Electric Signals ◽  
Recent Laboratory

Abstract. Recent laboratory measurements on rocks under varying pressure lead to results which strengthen a model suggested by the author for the explanation of the power law relation that interconnects the lead time of Seismic Electric Signals and earthquake stress drop. In addition, recent applications of a thermodynamic model that interrelates the defect parameters in materials of geophysical interest and their bulk properties open a new window to further advance the aforementioned explanation.

A Lagrangian Reactive Transport Simulator with Successive Paths and Stationary-States: Concepts, Implementation and Verification

1989 ◽  
Vol 176 ◽  
Author(s):  
R. B. Knapp
Keyword(s):  
Reference Frame ◽  
Peclet Number ◽  
Software Package ◽  
Reactive Transport ◽  
Quantitative Agreement ◽  
Stationary States ◽  
Good Quantitative Agreement ◽  
Analytical Results ◽  
Single Path ◽  
Aqueous Species

ABSTRACTA geochemical software package which models static, single-path kinetic water-rock interactions, EQ3/6, has been modified to incorporate successive-paths and stationary states under high Peclet number transport conditions in a Lagrangian reference frame. These modifications permit calculation of reactive transport with reasonable computational requirements. Results from the new option in EQ3/6 have been compared with analytical results for the simple HC1 - SiO2 system; excellent agreements were achieved. Results have also been compared with published results for a portion of the A12O3 - HCI - K2O - SiO2 system. The results are in good qualitative and, in some cases, good quantitative agreement. However, the values of some variables differ substantially; these differences can be attributed to use of a different set of Al and Si aqueous species.

Evolution of Matt Surface Topography in Aluminium Pack Rolling

2005 ◽  
Author(s):  
Hiroshi Utsunomiya ◽  
Michael P. F. Sutcliffe ◽  
Hugh R. Shercliff ◽  
Pete S. Bate ◽  
Dan B. Miller
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Surface Topography ◽  
Material Properties ◽  
Quantitative Agreement ◽  
Aluminium Foil ◽  
The Finite Element Method ◽  
Good Quantitative Agreement ◽  
Pack Rolling ◽  
Element Method

Roughening of the matt surface of pack rolled aluminium foil has been modelled. The model is based on the finite element method using isotropic plasticity. A distribution in material properties has been used to simulate the distribution of orientations through the material. The predictions of roughness show good quantitative agreement with the experiments.

Recent Laboratory Measurements ofD- andE-Region Ion-Neutral Reactions

Radio Science ◽  
1972 ◽  
Vol 7 (1) ◽  
pp. 113-115 ◽  
Author(s):  
F. C. Fehsenfeld ◽  
E. E. Ferguson
Keyword(s):  
Laboratory Measurements ◽  
Recent Laboratory
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