Wavelet application to the magnetic field turbulence in the upstream region of the Martian bow shock

Tarasov, V. G.; Dubinin, E.; Perraut, S.; Roux, A.; Sauer, K.; Skalsky, A.; Delva, M.

doi:10.1186/bf03352163

Cited by 13 publications

(5 citation statements)

References 27 publications

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“…Skalsky et al (1992Skalsky et al ( , 1993 have demonstrated that the high frequency emissions at the leading edge of the foreshock are correlated with the enhanced electron fluxes streaming into the solar hemisphere along the magnetic field line. Tarasov et al (1998) presented the evidence that the ULF fluctuations of the magnetic field were observed simultaneously with the appearance of ions reflected at the Martian bow shock and gyrating in the upstream region (Dubinin et al, 1994(Dubinin et al, , 1995. All these phenomena have allowed to postulate the presence of a well developed foreshock upstream the Martian bow shock which is formally similar to that known from wave and plasma observations at Earth (Tsurutani and Rodriguez, 1981 and references therein).…”

Section: Introductionsupporting

confidence: 49%

“…The ULF emissions measured in the frequency range between 0.2 and 10 Hz gradually increase in their amplitudes through out the entire foreshock region and their maximum intensities are recorded close to the shock front. Tarasov et al (1998) have shown that the local enhancements of the ULF magnetic oscillations were observed around the proton cyclotron frequency inside the Wave modes, which are typical for the electron and ion foreshock are indicated.…”

Section: Wave Observations In the Foreshock Region At Marsmentioning

confidence: 97%

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Wave observations at the foreshock boundary in the near-Mars space

et al. 2014

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Wave and plasma measurements carried out by the Phobos-2 spacecraft in the Martian environment indicate that a part of solar wind electrons and ions are reflected and accelerated at the Martian bow shock. These particles streaming back into the solar wind lead to the formation of the foreshock region upstream the planetary bow shock. It is shown that the general structure of the foreshock at Mars is similar to that of the foreshock region upstream the Earth's bow shock. However, the electric emissions observed at frequencies around 100 Hz at the leading edge of electron foreshock at Mars have been never reported for observations in the similar region at Earth. The burst of these waves occurs before the spacecraft enters the electron foreshock identified with the onset of electron plasma waves and calculations of the magnetic connection to the planetary bow shock.

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Section: Introductionsupporting

confidence: 49%

Section: Wave Observations In the Foreshock Region At Marsmentioning

confidence: 97%

Wave observations at the foreshock boundary in the near-Mars space

et al. 2014

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“… Torrence and Compo [1998] provide a clear introduction to wavelet analysis and its application to geophysical signals. Tarasov et al [1998] give an example of its application to oscillations upstream of the Martian bow shock.…”

Section: Discussionmentioning

confidence: 99%

“…At Mars, detailed observations of plasma waves started with Phobos 2 [ Riedler et al , 1989; Grard et al , 1989; Sagdeev et al , 1990]. ULF waves near the proton gyrofrequency have been observed upstream of the Martian bow shock using both Phobos 2 data [ Russell et al , 1990, 1992; Tarasov et al , 1998; Delva and Dubinin , 1998] and MGS data [ Brain et al , 2002]. Initial reports of ULF waves within the magnetosheath and the magnetic pileup region as observed by MGS have also been made [ Cloutier et al , 1999; Crider , 1999; Bertucci et al , 2003b; Grebowsky et al , 2003].…”

Section: Introductionmentioning

confidence: 99%

Observations of low‐frequency magnetic oscillations in the Martian magnetosheath, magnetic pileup region, and tail

et al. 2004

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[1] Observations are presented of low-frequency magnetic oscillations in the Martian magnetosheath, magnetic pileup region, and tail as observed by the Magnetometer/ Electron Reflectometer experiment on board Mars Global Surveyor. Within the dayside magnetosheath the oscillations are found to be predominantly compressional, elliptically polarized waves with wave vectors that have large angles relative to the mean field and dominant frequencies that are significantly below the local proton gyrofrequency. On the basis of these observations we identify these oscillations as mirror mode instabilities. In the nightside magnetosheath the oscillations are predominantly transverse and elliptical, and they propagate at smaller angles relative to the mean field at frequencies within a factor of 2-10 less than the local proton gyrofrequency. These characteristics lead us to associate these oscillations with ion/ion-resonant instabilities that arise from counterstreaming plasma populations such as the solar wind and pickup ions of planetary origin. Within the magnetic pileup region and tail the oscillations have considerably smaller amplitudes and are linearly polarized, obliquely propagating, ultralow-frequency oscillations which may be a mix of multiple wave modes.

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“…For the same orbit, the magnetic field magnitude is plotted in Fig. 2(a) together with the low-frequency magnetic spectrum as result of a wavelet analysis (Tarasov et al, 1998). Just at the time (UT ≈ 04:55) where the "Phobos event" is seen as a strong magnetic field perturbation, a significant wave emission occurs near the proton cyclotron frequency Ω p (traced by a red line).…”

Section: The Phobos Eventsmentioning

confidence: 99%

Low-frequency electromagnetic waves and instabilities within the Martian bi-ion plasma

et al. 2014

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The Martian environment is characterized by the presence of heavy (oxygen) ions of planetary origin which strongly influence the solar wind dynamics, including the bow shock structure and position and may cause additional plasma boundaries in the magnetosheath. In this paper the dispersion characteristics of low-frequency electromagnetic waves (LFEW) in the proton gyrofrequency range are studied. The excitation of these waves results from the relative motion between the solar wind protons and planetary heavy ions, which are considered as unmagnetized and, therefore, may act like a beam in the solar wind. The model takes into account the small extension of the Martian magnetosphere compared with the pickup gyroradius of an exospheric ion. From the dispersion analysis it was found that the most unstable waves with relatively high growth rates propagate oblique to the ambient magnetic field. For small propagation angle to the magnetic field these are right-hand polarized whistler waves in the solar wind frame, and due to Doppler shift they appear near to the proton cyclotron frequency as left-hand polarized waves in the beam (spacecraft) frame. We suggest that the sporadic LFEW emission as seen in the upstream region of Mars by Phobos-2 may indicate the existence of localized "heavy ion bunches" whose origin is relatively unclear, but a possible relation to the Martian moons cannot be excluded. Especially, the socalled Phobos events marked by spectral peaks around the proton cyclotron frequency may be interpreted as signatures of the solar wind interaction with a tenuous gas torus. A comparable situation is known from the AMPTE Ba and Li releases where during the late stages of the experiments an enhanced proton cyclotron emission was observed as well. Another important aspect of LFEW excitation is its role in proton deceleration and heating upstream the bow shock where turbulent processes may provide a strong momentum coupling between the solar wind and the newly generated ions of planetary origin.

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Wavelet application to the magnetic field turbulence in the upstream region of the Martian bow shock

Cited by 13 publications

References 27 publications

Wave observations at the foreshock boundary in the near-Mars space

Wave observations at the foreshock boundary in the near-Mars space

Observations of low‐frequency magnetic oscillations in the Martian magnetosheath, magnetic pileup region, and tail

Low-frequency electromagnetic waves and instabilities within the Martian bi-ion plasma

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