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| Titel |
Still one possibility to determine the wave vector onboard one spacecraft |
| VerfasserIn |
Valery Korepanov, Fedir Dudkin |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250046440
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| Zusammenfassung |
| Lviv Centre of Institute for Space Research, Lviv, Ukraine (vakor@isr.lviv.ua/+380 32
2639163)
The determination of dispersion relations k = k(Ï ) for the wave, propagating
in space plasmas is an important task of electromagnetic measurements onboard
satellites. By this the major problem is to separate the spatial and temporal variations
of electromagnetic fields. The wave vector calculation in general case requires
measurement of three components of magnetic field B vector and three components of
electric field E vector. The measurement of the electric field E with enough good
precision requires long booms what is a great problem to realize, especially onboard
of microsatellites. We study the possibility to avoid E measurements without of
loss of wave vector k calculations generality and precision. Basing on Maxwell’s
equation
- à B = μJ
where B, J are vectors of magnetic field and current density respectively and decomposing
EM wave in plasma into spectrum of plane waves
BË= BË exp(- jkr), JË= ËJ exp(- jkr),
0 0
where j = (-1)0.5, k is wave vector, r is radius-vector, we also assume that the space
derivatives of magnetic field and current density amplitudes are very small. Then the system
of 3 equations which allows calculating the wave vector components by using data from
3-component magnetometer and 2-component current density meter for each spectral
component of EM wave, or, in other words, dispersion relations k = k(Ï), may be
composed.
Such data can be provided by a set of combined sensors (so-called Wave Probe, reference
below) each of which consists of a magnetic field sensor and a current density sensor
mounted in one case. Obviously, we can neglect EM wave non-uniformity for such a small
device.
We have to mention also that these considerations can be applied to known and steady
space configurations. (It is supposed that crossing time over a current structure by measuring
device is less than characteristic time of structure change). For example, auroral structures
can be considered as invariable for satellite transition time across these ones. In
addition to that, the magnetic field aligned currents are considered as plane current
sheets. The same approach can be applied to currents in magnetopause or bow shock
region.
The details of the proposed method and corresponding instrumentation description are
presented. Also the space experiment preliminary results are discussed which confirm the
fundamental correctness of the calculations.
This study was partially supported by NSAU contract 1-05/08.
Reference:
Dudkin, F., Korepanov, V., Lizunov, G.., Experiment VARIANT - first results from
Wave Probe instrument, Advances in Space Research, 43, pp. 1904-1909, 2009. |
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