Rosetta spacecraft influence on the mutual impedance probe frequency response in the long Debye length mode

2001 ◽  
Vol 49 (6) ◽  
pp. 633-644 ◽  
Author(s):  
J. Geiswiller ◽  
C. Béghin ◽  
E. Kolesnikova ◽  
D. Lagoutte ◽  
J.L. Michau ◽  
...  
Keyword(s):  
Frequency Response ◽  
Debye Length ◽  
Mutual Impedance ◽  
Impedance Probe ◽  
Probe Frequency

Theory of the mutual impedance of two small dipoles in a warm isotropic plasma

1975 ◽  
Vol 14 (2) ◽  
pp. 209-243 ◽  
Author(s):  
R. Pottelette ◽  
B. Rooy ◽  
V. Fiala
Keyword(s):  
Distribution Function ◽  
Frequency Response ◽  
Electron Density ◽  
Debye Length ◽  
Second Step ◽  
Isotropic Plasma ◽  
Transfer Impedance ◽  
Mutual Impedance ◽  
Maxwellian Plasma ◽  
Electron Density And Temperature

We show theoretically that the electron density and temperature of a plasma could be deduced from the measurements of the transfer impedance between two small dipole antennae, each much shorter than a Debye length, separated by a distance of ten or more Debye lengths. In contrast to the quadripole probe, this ‘double-dipole probe’ relies on not producing perturbations in the plasma, rather than on minimizing their effects. The plasma is assumed to be warm and isotropic, and the motion of the ions is neglected. First, it is shown that, in a Maxwellian plasma, the frequency response of a double-dipole probe is easier to interpret than that of a quadripole probe with the customary square layout. Then, in a second step, the transfer impedance of the former probe is calculated in a Cauchy plasma, and the results are compared with those previously obtained in a Maxwellian plasma. By so doing, we show that, for large distances between the dipoles, the real part of the transfer impedance is sensitive to the form of the tail of the distribution function.

Improved MoM-PO-Based Technique for Wideband Analysis of Antennas around Large Platforms

2012 ◽  
Vol 629 ◽  
pp. 646-648
Author(s):  
Ji Ma ◽  
Shu Xi Gong ◽  
Qian Wang
Keyword(s):  
Frequency Response ◽  
Method Of Moments ◽  
Hybrid Method ◽  
Wide Band ◽  
Numerical Results ◽  
Physical Optics ◽  
Impedance Matrix ◽  
Mutual Impedance ◽  
Interpolation Technique ◽  
Matrix Interpolation

An improved wide-band analysis which combines the hybrid method of moments-physical optics (MoM-PO) formula with impedance matrix interpolation technique for antennas around large platforms is presented. The algorithm proposed in this paper interpolated the mutual impedance matrix between MoM and PO regions rather than the MoM self-matrix. This practice can result in more accurate frequency response than the conventional approach. Sample numerical results demonstrate the capability of the algorithm.

scholarly journals RPC-MIP observations at comet 67P/Churyumov-Gerasimenko explained by a model including a sheath and two populations of electrons

2019 ◽  
Vol 630 ◽  
pp. A41 ◽  
Author(s):  
G. Wattieaux ◽  
N. Gilet ◽  
P. Henri ◽  
X. Vallières ◽  
L. Bucciantini
Keyword(s):  
Collisionless Plasma ◽  
Plasma Sheath ◽  
Sheath Thickness ◽  
Mutual Impedance ◽  
Cometary Plasma ◽  
Rosetta Mission ◽  
Impedance Probe ◽  
First Time ◽  
Two Populations ◽  
Comet 67P

The response of the mutual impedance probe RPC-MIP on board Rosetta orbiter electrostatically modeled considering an unmagnetized and collisionless plasma with two Maxwellian electron populations. A vacuum sheath surrounding the probe was considered in our model in order to take the ion sheath into account that is located around the probe, which is immersed in the cometary plasma. For the first time, the simulated results are consistent with the data collected around comet 67P/Churyumov-Gerasimenko (67P), but strong discrepancies were identified with the previous simulations that neglected the plasma sheath around the probe. We studied the influence of the sheath thickness and of the electron populations. This work helps to better understand the initially unexpected responses of the mutual impedance probe that were acquired during the Rosetta mission. It suggests that two electron populations exist in the cometary plasma of 67P.

Theoretical cross-spectrum of the microfield measured by two small dipoles in a warm isotropic plasma

1977 ◽  
Vol 17 (2) ◽  
pp. 201-231 ◽  
Author(s):  
R. Pottelette ◽  
C. Chauliaguet ◽  
L. R. O. Storey
Keyword(s):  
Magnetic Field ◽  
Thermal Equilibrium ◽  
Plasma Frequency ◽  
Debye Length ◽  
Resonance Peak ◽  
Isotropic Plasma ◽  
Main Resonance ◽  
Mutual Impedance ◽  
Cross Spectrum ◽  
Electron Density And Temperature

We suggest that the electron density and temperature of a plasma could be determined by immersing two small dipole antennae in it, and by measuring, as a function of frequency, the cross-spectrum of the random signals that they receive. When the plasma is in thermal equilibrium, this spectrum is related simply, by Nyquist's theorem, to the real part of the mutual impedance of the two antennae. We have studied the case where, in addition, the plasma is collisionless and no magnetic field is present. The spectrum has a main resonance peak slightly above the plasma frequency, while for still higher frequencies it exhibits oscillations, the amplitudes of which decrease as one moves away from the plasma frequency. The main resonance peak becomes sharper, but smaller, as the distance between the antennae becomes large compared with the Debye length.

scholarly journals Plasma characterization at comet 67P between 2 and 4 AU from the Sun with the RPC-MIP instrument

2020 ◽  
Vol 638 ◽  
pp. A124
Author(s):  
Gaëtan Wattieaux ◽  
Pierre Henri ◽  
Nicolas Gilet ◽  
Xavier Vallières ◽  
Jan Deca
Keyword(s):  
Temperature Ratio ◽  
Electron Densities ◽  
Plasma Parameters ◽  
Mutual Impedance ◽  
Rosetta Mission ◽  
Fluctuation Range ◽  
Impedance Probe ◽  
Cold Electrons ◽  
Two Populations ◽  
Comet 67P

The plasma of comet 67P/Churyumov-Gerasimenko is analyzed based on the RPC-MIP mutual impedance probe data of the Rosetta mission. Numerical simulations of the RPC-MIP instrumental response considering two populations of electrons were fit on experimental responses acquired from January to September 2016 to extract the electron densities and temperatures. A time-tracking of the plasma parameters was performed, leading to the identification of a cold and a warm population of electrons during the period of interest. The respective densities and temperatures lie in the ranges [100; 1000] cm−3 and [0.05; 0.3] eV for the cold electrons and in the ranges [50; 500] cm−3 and [2; 10] eV for the warm electrons. Warm electrons most of the time made up between 10 and 30% of the whole population, while the temperature ratio between warm and cold electrons lay mostly between 30 and 70 during the period we studied. The fluctuation range of the plasma parameters, that is, the electron densities and temperatures, appears to have remained rather constant during the last nine months of the mission. We take the limitations of the instrument that are due to the experimental noise into account in our discussion of the results.

scholarly journals The electrical properties of Titan’s surface at the Huygens landing site measured with the PWA–HASI Mutual Impedance Probe. New approach and new findings

Icarus ◽  
2016 ◽  
Vol 270 ◽  
pp. 272-290 ◽  
Author(s):  
Michel Hamelin ◽  
Anthony Lethuillier ◽  
Alice Le Gall ◽  
Réjean Grard ◽  
Christian Béghin ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Landing Site ◽  
New Approach ◽  
Mutual Impedance ◽  
New Findings ◽  
Impedance Probe

scholarly journals Analysis of Simulated Axial-Flow Turbomachine Wakes for Estimation of Frequency-Response Requirements for Fast-Response Pressure Probes

1974 ◽  
Author(s):  
G. H. Junkhan
Keyword(s):  
Frequency Response ◽  
Axial Flow ◽  
Fast Response ◽  
Maximum Pressure ◽  
Pressure Time ◽  
Total Head ◽  
Blade Row ◽  
Probe Frequency ◽  
Response Pressure ◽  
Electronic Filters

Various types of fast-response pressure probes are currently used in turbomachines. One application of these probes is for the measurement of time varying total pressures downstream of an aixal-flow machine rotor. In this paper, the frequency-response requirements for a probe placed in such a stream are estimated using a simulated wake pressure-time function. The analysis indicates that the minimum required response depends mainly on the maximum pressure difference from wake to free stream, the blade passing frequency and the blade row geometry. One of the assumptions made in the analysis is that a fast-response probe with a short total head tube in front of the transducer behaves approximately as a second-order dynamic system. Experimental results are given to illustrate probe behavior both in frequency-response tests and behind an axial-flow rotor. Improved probe frequency response using electronic filters is also illustrated.

Sign in / Sign up

Export Citation Format

Share Document