Determination of the wave-vector spectrum for plasma waves and turbulence observed in space plasmas

1992 ◽  
Vol 54 (10) ◽  
pp. 1227-1235 ◽  
Author(s):  
F. Lefeuvre ◽  
J.L. Pinçon
Keyword(s):  
Wave Vector ◽  
Plasma Waves ◽  
Space Plasmas

scholarly journals Determination of wave vectors using the phase differencing method

2013 ◽  
Vol 31 (9) ◽  
pp. 1611-1617 ◽  
Author(s):  
S. N. Walker ◽  
I. Moiseenko
Keyword(s):  
Wave Packet ◽  
Correlation Length ◽  
Coherence Length ◽  
Low Frequency ◽  
Plasma Waves ◽  
Mhd Waves ◽  
Space Plasmas ◽  
The Waves ◽  
Theoretical Results

Abstract. Due to the collisionless nature of space plasmas, plasma waves play an important role in the redistribution of energy between the various particle populations in many regions of geospace. In order to fully comprehend such mechanisms it is necessary to characterise the nature of the waves present. This involves the determination of properties such as wave vector k. There are a number of methods used to calculate k based on the multipoint measurements that are now available. These methods rely on the fact that the same wave packet is simultaneously observed at two or more locations whose separation is small in comparison to the correlation length of the wave packet. This limitation restricts the analysis to low frequency (MHD) waves. In this paper we propose an extension to the phase differencing method to enable the correlation of measurements that were not made simultaneously but differ temporally by a number of wave periods. The method is illustrated using measurements of magnetosonic waves from the Cluster STAFF search coil magnetometer. It is shown that it is possible to identify wave packets whose coherence length is much less than the separation between the measurement locations. The resulting dispersion is found to agree with theoretical results.

Multipayload interferometric wave vector determination of auroral hiss

2012 ◽  
Vol 117 (A2) ◽  
pp. n/a-n/a ◽  
Author(s):  
E. T. Lundberg ◽  
P. M. Kintner ◽  
S. P. Powell ◽  
K. A. Lynch
Keyword(s):  
Wave Vector ◽  
Auroral Hiss

scholarly journals Instantaneous local wave vector estimation from multi-spacecraft measurements using few spatial points

2004 ◽  
Vol 22 (7) ◽  
pp. 2633-2641 ◽  
Author(s):  
T. D. Carozzi ◽  
A. M. Buckley ◽  
M. P. Gough
Keyword(s):  
Signal Processing ◽  
Phase Velocity ◽  
Wave Vector ◽  
Direct Determination ◽  
Space Mission ◽  
3 Dimensional ◽  
Local Wave ◽  
Local Properties ◽  
Vector Estimation

Abstract. We introduce a technique to determine instantaneous local properties of waves based on discrete-time sampled, real-valued measurements from 4 or more spatial points. The technique is a generalisation to the spatial domain of the notion of instantaneous frequency used in signal processing. The quantities derived by our technique are closely related to those used in geometrical optics, namely the local wave vector and instantaneous phase velocity. Thus, this experimental technique complements ray-tracing. We provide example applications of the technique to electric field and potential data from the EFW instrument on Cluster. Cluster is the first space mission for which direct determination of the full 3-dimensional local wave vector is possible, as described here.

Linear mode analysis in multi-ion plasmas

1997 ◽  
Vol 58 (2) ◽  
pp. 205-221 ◽  
Author(s):  
G. MANN ◽  
P. HACKENBERG ◽  
E. MARSCH
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Heavy Ions ◽  
Plasma Waves ◽  
Mode Analysis ◽  
Space Plasmas ◽  
Minor Components ◽  
Linear Mode ◽  
Component Plasma

Heavy ions frequently appear as minor components in space plasmas, for example in the solar wind and in the vicinity of comets. Both the different components of ions and the associated plasma waves are observed by extraterrestrial in situ measurements. The influence of these ion components on the properties of plasma waves is investigated by means of the multi-fluid equations. The linear mode analysis is performed numerically for a three-component plasma with an ambient magnetic field. Both the dispersion relations and the polarizations of the freely propagating wave modes are given and subsequently discussed.

Collisionless damping of plasma waves as a real physical phenomenon does not exist

2014 ◽  
Vol 6 (3) ◽  
pp. 1291-1296
Author(s):  
V. N. Soshnikov
Keyword(s):  
Energy Conservation ◽  
Dispersion Equation ◽  
Physical Phenomenon ◽  
Harmonic Wave ◽  
Collisionless Plasma ◽  
Plasma Waves ◽  
Wave Number ◽  
Erroneous Statement ◽  
Complex Dispersion

Trivial logic of collisionless plasma waves is reduced to using complex exponentially damping/growing wave functions to obtain a complex dispersion equation for their wave number 1 k and the decrement/increment 2 k (for a given real frequency  and complex wave number k  k1  ik2 ), whose solutions are ghosts 1 2 k , k which do not have anything to do at 2 k  0 with the real solution of the dispersion equation for the initial exponentially damping/growing real plasma waves with the physically observable quantities 1 2 k , k , for which finding should be added, in this case, the second equation of the energy conservation law. Using a complex dispersion equation for the simultaneous determination of 1 k and 2 k violates the law of energy conservation, leads to a number of contradictions, is logical error, and finally also the mathematical error leading to both erroneous statement on the possible existence of exponentially damping/growing harmonic wave solutions and to erroneous values 1 k and 2 k . Mathematically correct conclusion about the damping/growing of virtual complex waves of collisionless plasma is wrongly attributed to the actual real plasma waves.

scholarly journals On the Calculation of the Effective Polytropic Index in Space Plasmas

Entropy ◽  
2019 ◽  
Vol 21 (10) ◽  
pp. 997 ◽  
Author(s):  
Georgios Nicolaou ◽  
George Livadiotis ◽  
Robert T. Wicks
Keyword(s):  
Plasma Density ◽  
Plasma Temperature ◽  
Statistical Error ◽  
Space Plasmas ◽  
Polytropic Index ◽  
Plasma Measurement ◽  
Wind Spacecraft ◽  
Index Value ◽  
The Relationship

The polytropic index of space plasmas is typically determined from the relationship between the measured plasma density and temperature. In this study, we quantify the errors in the determination of the polytropic index, due to uncertainty in the analyzed measurements. We model the plasma density and temperature measurements for a certain polytropic index, and then, we apply the standard analysis to derive the polytropic index. We explore the accuracy of the derived polytropic index for a range of uncertainties in the modeled density and temperature and repeat for various polytropic indices. Our analysis shows that the uncertainties in the plasma density introduce a systematic error in the determination of the polytropic index which can lead to artificial isothermal relations, while the uncertainties in the plasma temperature increase the statistical error of the calculated polytropic index value. We analyze Wind spacecraft observations of the solar wind protons and we derive the polytropic index in selected intervals over 2002. The derived polytropic index is affected by the plasma measurement uncertainties, in a similar way as predicted by our model. Finally, we suggest a new data-analysis approach, based on a physical constraint, that reduces the amount of erroneous derivations.

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