scholarly journals Oxygen Ion Energization at Mars: Comparison of MAVEN and Mars Express Observations to Global Hybrid Simulation

2018 ◽  
Vol 123 (2) ◽  
pp. 1678-1689 ◽  
Author(s):  
R. Jarvinen ◽  
D. A. Brain ◽  
R. Modolo ◽  
A. Fedorov ◽  
M. Holmström
Keyword(s):  
Hybrid Simulation ◽  
Mars Express ◽  
Oxygen Ion ◽  
Ion Energization

scholarly journals The structure of high altitude O<sup>+</sup> energization and outflow: a case study

2004 ◽  
Vol 22 (7) ◽  
pp. 2497-2506 ◽  
Author(s):  
H. Nilsson ◽  
S. Joko ◽  
R. Lundin ◽  
H. Rème ◽  
J.-A. Sauvaud ◽  
...  
Keyword(s):  
High Altitude ◽  
Flow Direction ◽  
Correlation Coefficients ◽  
Dispersion Analysis ◽  
Observation Point ◽  
Ion Density ◽  
Oxygen Ion ◽  
Ion Energization ◽  
Upstream Flow

Abstract. Multi-spacecraft observations from the CIS ion spectrometers on board the Cluster spacecraft have been used to study the structure of high-altitude oxygen ion energization and outflow. A case study taken from 12 April 2004 is discussed in more detail. In this case the spacecraft crossed the polar cap, mantle and high-altitude cusp region at altitudes between 4RE and 8RE and 2 of the spacecraft provided data. The oxygen ions were seen as a beam with narrow energy distribution, and increasing field-aligned velocity and temperature at higher altitude further in the upstream flow direction. The peak O+ energy was typically just above the highest energy of observed protons. The observed energies reached the upper limit of the CIS ion spectrometer, i.e. 38keV. Moment data from the spacecraft have been cross-correlated to determine cross-correlation coefficients, as well as the phase delay between the spacecraft. Structures in ion density, temperature and field-aligned flow appear to drift with the observed field-perpendicular drift. This, together with a velocity dispersion analysis, indicates that much of the structure can be explained by transverse heating well below the spacecraft. However, temperature isotropy and the particle flux as a function of field-aligned velocity are inconsistent with a single altitude Maxwellian source. Heating over extended altitude intervals, possibly all the way up to the observation point, seem consistent with the observations.

scholarly journals Oxygen ion energization by waves in the high altitude cusp and mantle

2012 ◽  
Vol 30 (9) ◽  
pp. 1309-1314 ◽  
Author(s):  
M. Waara ◽  
H. Nilsson ◽  
R. Slapak ◽  
M. André ◽  
G. Stenberg
Keyword(s):  
High Altitude ◽  
Low Frequency ◽  
Wave Activity ◽  
Clear Correlation ◽  
Particle Theory ◽  
Temperature Ratio ◽  
Particle Distributions ◽  
Oxygen Ion ◽  
Ion Energization ◽  
Particle Approach

Abstract. We present a comparative study of low frequency electric field spectral densities and temperatures observed by the Cluster spacecraft in the high altitude cusp/mantle region. We compare the relation between the O+ temperature and wave intensity at the oxygen gyrofrequency at each measurement point and find a clear correlation. The trend of the correlation agrees with the predictions by both an asymptotic mean-particle theory and a test-particle approach. The perpendicular to parallel temperature ratio is also consistent with the predictions of the asymptotic mean-particle theory. At times the perpendicular temperature is significantly higher than predicted by the models. A simple study of the evolution of the particle distributions (conics) at these altitudes indicates that enhanced perpendicular temperatures would be observed over many RE after heating ceases. Therefore, sporadic intense heating is the likely explanation for cases with high temperature and comparably low wave activity. We observe waves of sufficient amplitude to explain the highest observed temperatures, while the theory in general overestimates the temperature associated with the highest observed wave activity, indicating that such high wave activity is very sporadic.

scholarly journals Comparison of plasma data from ASPERA-3/Mars-Express with a 3-D hybrid simulation

2007 ◽  
Vol 25 (8) ◽  
pp. 1851-1864 ◽  
Author(s):  
A. Bößwetter ◽  
S. Simon ◽  
T. Bagdonat ◽  
U. Motschmann ◽  
M. Fränz ◽  
...  
Keyword(s):  
Solar Wind ◽  
Hybrid Simulation ◽  
Bow Shock ◽  
Proton Density ◽  
Model Calculations ◽  
Mars Express ◽  
Characteristic Features ◽  
Hybrid Approximation ◽  
Individual Particles ◽  
Characteristic Scales

Abstract. The ELS and IMA sensors of the ASPERA-3 experiment onboard of Mars-Express (MEX) can measure electron as well as ion moments. We compare these measurements for a specific orbit with the simulation results from a 3-D hybrid model. In the hybrid approximation the electrons are modeled as a massless charge-neutralizing fluid, whereas the ions are treated as individual particles. This approach allows gyroradius effects to be included in our model calculations of the Martian plasma environment because the gyroradii of the solar wind protons are in the range of several hundred kilometers and therefore comparable with the characteristic scales of the subsolar ionospheric interaction region. The position of both the bow shock and the Ion Composition Boundary (ICB) manifest in the MEX data as well as in the results from the hybrid simulation nearly at the same location. The characteristic features of these boundaries, i.e. an increase of proton density and temperature at the Bow Shock and a transition from solar wind to ionospheric particles at the ICB, are clearly identifiable in the data.

scholarly journals Oxygen ion energization observed at high altitudes

2010 ◽  
Vol 28 (4) ◽  
pp. 907-916 ◽  
Author(s):  
M. Waara ◽  
H. Nilsson ◽  
G. Stenberg ◽  
M. André ◽  
H. Gunell ◽  
...  
Keyword(s):  
Geomagnetic Field ◽  
Distribution Functions ◽  
High Altitudes ◽  
Polar Cap ◽  
Wave Fields ◽  
Oxygen Ions ◽  
Oxygen Ion ◽  
Ion Energization ◽  
Heating Up

Abstract. We present a case study of significant heating (up to 8 keV) perpendicular to the geomagnetic field of outflowing oxygen ions at high altitude (12 RE) above the polar cap. The shape of the distribution functions indicates that most of the heating occurs locally (within 0.2–0.4 RE in altitude). This is a clear example of local ion energization at much higher altitude than usually reported. In contrast to many events at lower altitudes, it is not likely that the locally observed wave fields can cause the observed ion energization. Also, it is not likely that the ions have drifted from some nearby energization region to the point of observation. This suggests that additional fundamentally different ion energization mechanisms are present at high altitudes. One possibility is that the magnetic moment of the ions is not conserved, resulting in slower outflow velocities and longer time for ion energization.

scholarly journals Oxygen ion escape from Venus in a global hybrid simulation: role of the ionospheric O<sup>+</sup> ions

2009 ◽  
Vol 27 (11) ◽  
pp. 4333-4348 ◽  
Author(s):  
R. Jarvinen ◽  
E. Kallio ◽  
P. Janhunen ◽  
S. Barabash ◽  
T. L. Zhang ◽  
...  
Keyword(s):  
Solar Wind ◽  
Hybrid Simulation ◽  
Solar Wind Interaction ◽  
Simulation Code ◽  
Oxygen Ion ◽  
Ion Escape ◽  
Global Configuration ◽  
Best Fit ◽  
The Magnetic Field

Abstract. We study the solar wind induced oxygen ion escape from Venus' upper atmosphere and the Venus Express observations of the Venus-solar wind interaction by the HYB-Venus hybrid simulation code. We compare the simulation to the magnetic field and ion observations during an orbit of nominal upstream conditions. Further, we study the response of the induced magnetosphere to the emission of planetary ions. The hybrid simulation is found to be able to reproduce the main observed regions of the Venusian plasma environment: the bow shock (both perpendicular and parallel regions), the magnetic barrier, the central tail current sheet, the magnetic tail lobes, the magnetosheath and the planetary wake. The simulation is found to best fit the observations when the planetary \\oxy~escape rate is in the range from 3×1024 s−1 to 1.5×1025 s−1. This range was also found to be a limit for a test particle-like behaviour of the planetary ions: the higher escape rates manifest themselves in a different global configuration of the Venusian induced magnetosphere.

Ion escape at Mars: Comparison of a 3-D hybrid simulation with Mars Express IMA/ASPERA-3 measurements

Icarus ◽  
2006 ◽  
Vol 182 (2) ◽  
pp. 350-359 ◽  
Author(s):  
E. Kallio ◽  
A. Fedorov ◽  
E. Budnik ◽  
T. Säles ◽  
P. Janhunen ◽  
...  
Keyword(s):  
Hybrid Simulation ◽  
Mars Express ◽  
Ion Escape

Analysis of Silicon-On-Insulator Structures Formed By Oxygen Ion Implantation

1985 ◽  
Vol 43 ◽  
pp. 300-301
Author(s):  
N. Lewis ◽  
E. L. Hall ◽  
A. Mogro-Campero ◽  
R. P. Love
Keyword(s):  
Ion Implantation ◽  
Single Crystal ◽  
Single Crystal Silicon ◽  
Silicon Layer ◽  
Device Fabrication ◽  
Silicon On Insulator ◽  
High Dose ◽  
Crystal Silicon ◽  
Oxygen Ion ◽  
Oxygen Ion Implantation

The formation of buried oxide structures in single crystal silicon by high-dose oxygen ion implantation has received considerable attention recently for applications in advanced electronic device fabrication. This process is performed in a vacuum, and under the proper implantation conditions results in a silicon-on-insulator (SOI) structure with a top single crystal silicon layer on an amorphous silicon dioxide layer. The top Si layer has the same orientation as the silicon substrate. The quality of the outermost portion of the Si top layer is important in device fabrication since it either can be used directly to build devices, or epitaxial Si may be grown on this layer. Therefore, careful characterization of the results of the ion implantation process is essential.

Sign in / Sign up

Export Citation Format

Share Document