scholarly journals Propagation and dispersion of electrostatic waves in the ionospheric E region

1997 ◽  
Vol 15 (7) ◽  
pp. 878-889 ◽  
Author(s):  
K. Iranpour ◽  
H. L. Pécseli ◽  
J. Trulsen ◽  
A. Bahnsen ◽  
F. Primdahl ◽  
...  
Keyword(s):  
Hall Current ◽  
Low Frequency ◽  
Plasma Waves ◽  
Electrostatic Waves ◽  
Field Fluctuations ◽  
E Region ◽  
Band Pass ◽  
Electrostatic Fluctuations ◽  
The Waves ◽  
The Rose

Abstract. Low-frequency electrostatic fluctuations in the ionospheric E region were detected by instruments on the ROSE rockets. The phase velocity and dispersion of plasma waves in the ionospheric E region are determined by band-pass filtering and cross-correlating data of the electric-field fluctuations detected by the probes on the ROSE F4 rocket. The results were confirmed by a different method of analysis of the same data. The results show that the waves propagate in the Hall-current direction with a velocity somewhat below the ion sound speed obtained for ionospheric conditions during the flight. It is also found that the waves are dispersive, with the longest wavelengths propagating with the lowest velocity.

Helicity waves propagating in a plasma

1991 ◽  
Vol 45 (3) ◽  
pp. 481-488 ◽  
Author(s):  
Z. Yoshida
Keyword(s):  
Magnetic Field ◽  
Faraday Effect ◽  
Low Frequency ◽  
Plasma Waves ◽  
Frequency Limit ◽  
High Frequencies ◽  
Transverse Modes ◽  
Longitudinal Part ◽  
The Waves ◽  
Perturbed Magnetic Field

There exist plasma waves that transport helicity although they do not propagate electromagnetic energy. The dispersion relations of such helicity waves are studied. The electric field of the waves is parallel to the perturbed magnetic field, and both are perpendicular to the perturbed current. In cross-field propagation, a helicity wave is decomposed into two transverse modes with different polarizations and a longitudinal part. The helicity waves are principally Alfvénic in the low-frequency limit. At high frequencies, the Faraday effect comes into the polarization.

scholarly journals On the new modes of planetary-scale electromagnetic waves in the ionosphere

2004 ◽  
Vol 22 (4) ◽  
pp. 1203-1211 ◽  
Author(s):  
G. D. Aburjania ◽  
K. Z. Chargazia ◽  
G. V. Jandieri ◽  
A. G. Khantadze ◽  
O. A. Kharshiladze
Keyword(s):  
Electromagnetic Waves ◽  
Large Scale ◽  
Low Frequency ◽  
Planetary Scale ◽  
Phase Velocities ◽  
F Region ◽  
E Region ◽  
General Dispersion ◽  
Fast Waves ◽  
The Waves

Abstract. Using an analogy method the frequencies of new modes of the electromagnetic planetary-scale waves (with a wavelength of 103 km or more), having a weather forming nature, are found at different ionospheric altitudes. This method gives the possibility to determine spectra of ionospheric electromagnetic perturbations directly from the dynamic equations without solving the general dispersion equation. It is shown that the permanently acting factor-latitude variation of the geomagnetic field generates fast and slow weakly damping planetary electromagnetic waves in both the E- and F-layers of the ionosphere. The waves propagate eastward and westward along the parallels. The fast waves have phase velocities (1–5)km s–1 and frequencies (10–1–10–4), and the slow waves propagate with velocities of the local winds with frequencies (10–4–10–6)s–1 and are generated in the E-region of the ionosphere. Fast waves having phase velocities (10-1500)km s–1 and frequencies (1–10–3)s–1 are generated in the F-region of the ionosphere. The waves generate the geomagnetic pulsations of the order of one hundred nanoTesla by magnitude. The properties and parameters of the theoretically studied electromagnetic waves agree with those of large-scale ultra-low frequency perturbations observed experimentally in the ionosphere. Key words. Ionosphere (ionospheric disturbances; waves propagation; ionosphere atmosphere interactions)

Mars-solar wind interaction in a global hybrid model: plasma waves and ion dynamics

2021 ◽  
Author(s):  
Riku Jarvinen ◽  
Esa Kallio ◽  
Tuija Pulkkinen
Keyword(s):  
Solar Wind ◽  
Large Scale ◽  
Low Frequency ◽  
Plasma Waves ◽  
Ion Dynamics ◽  
Solar Wind Interaction ◽  
3 Dimensional ◽  
Plasma Environment ◽  
A Charge ◽  
The Waves

<p>We discuss the solar wind interaction with Mars in a self-consistent, 3-dimensional global hybrid simulation, where ions are treated as macroscopic particle clouds moving under the Lorentz force and electrons form a charge-neutralizing fluid. In the model, ion populations include both the solar wind and planetary ions. We concentrate on the formation of plasma waves near Mars. Especially, we analyze properties of large-scale waves in the ion foreshock and their transmission in the magnetosheath. Further, we study the coupling of the waves with ion dynamics in the Martian plasma environment. We discuss the solar wind interaction with Mars in a self-consistent, 3-dimensional global hybrid simulation, where ions are treated as macroscopic particle clouds moving under the Lorentz force and electrons form a charge-neutralizing fluid. In the model, ion populations include both the solar wind and planetary ions. We concentrate on the formation of plasma waves near Mars. Especially, we analyze properties of large-scale waves in the ion foreshock and their transmission in the magnetosheath. Further, we study the coupling of the waves with ion dynamics in the Martian plasma environment. Finally, we compare these Mars simulations to our earlier global hybrid modeling of Venus and Mercury to investigate how the waves and ion dynamics depend on the distance from the Sun and the size of a planetary plasma environment.</p><p>References:</p><p>Jarvinen R., Alho M., Kallio E., Pulkkinen T.I., 2020, Oxygen Ion Escape From Venus Is Modulated by Ultra-Low Frequency Waves, Geophys. Res. Lett., 47, 11, doi:10.1029/2020GL087462</p><p>Jarvinen R., Alho M., Kallio E., Pulkkinen T.I., 2020, Ultra-low frequency waves in the ion foreshock of Mercury: A global hybrid modeling study, Mon. Notices Royal Astron. Soc., 491, 3, 4147-4161, doi:10.1093/mnras/stz3257 </p>

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.

Low-frequency electrostatic waves in a magnetized, current-free, heavy negative ion plasma

2013 ◽  
Vol 79 (6) ◽  
pp. 1107-1111 ◽  
Author(s):  
S. H. KIM ◽  
R. L. MERLINO ◽  
J. K. MEYER ◽  
M. ROSENBERG
Keyword(s):  
Large Fraction ◽  
Low Frequency ◽  
Negative Ions ◽  
Wave Mode ◽  
Negative Ion ◽  
Electrostatic Wave ◽  
Electrostatic Waves ◽  
Positive Ions ◽  
Ion Plasma ◽  
The Waves

AbstractWe report experimental observations of a low-frequency (≪ ion gyrofrequency) electrostatic wave mode in a magnetized cylindrical (Q machine) plasma containing positive ions, very few electrons and a relatively large fraction (n−/ne > 103) of heavy negative ions (m−/m+ ≈ 10), and no magnetic field-aligned current. The waves propagate nearly perpendicular to B with a multiharmonic spectrum. The maximum wave amplitude coincided spatially with the region of largest density gradient suggesting that the waves were excited by a drift instability in a nearly electron-free positive ion–negative ion plasma

scholarly journals Spectral properties of low-frequency electrostatic waves in the ionospheric E region

2000 ◽  
Vol 105 (A5) ◽  
pp. 10585-10601 ◽  
Author(s):  
B. Krane ◽  
H. L. Pécseli ◽  
J. Trulsen ◽  
F. Primdahl
Keyword(s):  
Spectral Properties ◽  
Low Frequency ◽  
Electrostatic Waves ◽  
E Region

scholarly journals Alfvén waves in the near-PSBL lobe: Cluster observations

2006 ◽  
Vol 24 (3) ◽  
pp. 1001-1013 ◽  
Author(s):  
T. Takada ◽  
R. Nakamura ◽  
W. Baumjohann ◽  
K. Seki ◽  
Z. Vörös ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Ion Beam ◽  
Low Frequency ◽  
Poynting Flux ◽  
Field Fluctuations ◽  
The Rich ◽  
Field Lines ◽  
The Waves ◽  
The Magnetic Field ◽  
Low Frequency Waves

Abstract. Electromagnetic low-frequency waves in the magnetotail lobe close to the PSBL (Plasma Sheet Boundary Layer) are studied using the Cluster spacecraft. The lobe waves show Alfvénic properties and transport their wave energy (Poynting flux) on average toward the Earth along magnetic field lines. Most of the wave events are rich with oxygen (O+) ion plasma. The rich O+ plasma can serve to enhance the magnetic field fluctuations, resulting in a greater likelihood of observation, but it does not appear to be necessary for the generation of the waves. Taking into account the fact that all events are associated with auroral electrojet enhancements, the source of the lobe waves might be a substorm-associated instability, i.e. some instability near the reconnection site, or an ion beam-related instability in the PSBL.

Magnetospheric sources of Pc1-2 ULF waves observed in the polar ionospheric waveguide

2002 ◽  
Vol 14 (1) ◽  
pp. 93-103 ◽  
Author(s):  
D.A. Neudegg ◽  
B.J. Fraser ◽  
F.W. Menk ◽  
G.B. Burns ◽  
R.J. Morris ◽  
...  
Keyword(s):  
Geomagnetic Field ◽  
Guided Waves ◽  
Low Frequency ◽  
Plasma Waves ◽  
Shear Mode ◽  
Ulf Waves ◽  
Fast Mode ◽  
Polar Ionosphere ◽  
Polar Cusp ◽  
The Waves

Energy from the outer regions of the magnetosphere may be transferred to the polar ionosphere by plasma waves. A magnetometer array operated during the Antarctic winter observed Ultra-Low-Frequency (ULF) plasma waves in the Pc 1–2 (0.1–10.0 Hz) frequency range, propagating parallel to the surface of the Earth in a waveguide or duct centred at ∼300 km altitude in the ionosphere. These compressional fast mode plasma waves most likely originated in the outer magnetosphere as shear mode plasma waves guided along the geomagnetic field. The region of origin in the magnetosphere for the waves is not certain as several widely spaced volumes map along geomagnetic field lines to a relatively close ensemble in the polar ionosphere. This paper compares the direction of propagation for the waves with signatures of magnetospheric regions geomagnetically projecting onto the ionosphere. Regions such as the polar cusp, low latitude boundary layer and mantle were observed by DMSP spacecraft and a SuperDARN high-frequency radar. The most likely region in the polar ionosphere for the fast mode waves to have originated from is equatorwards of the polar cusp, suggesting the field guided waves originated just inside the magnetopause. A case is made for association of the observed Pc1-2 ULF waves with post-noon, field-aligned-current systems driven by reconnection of the solar Interplanetary Magnetic Field (IMF) and the geomagnetic field near the magnetopause.

scholarly journals ULF wave transmission across collisionless shocks: 2.5D local hybrid simulations

2021 ◽  
Author(s):  
Primož Kajdič ◽  
Yann Pfau-Kempf ◽  
Lucile Turc ◽  
Andrew Dimmock ◽  
Minna Palmroth
Keyword(s):  
Magnetic Field ◽  
Low Frequency ◽  
Simulation Models ◽  
Ulf Waves ◽  
Collisionless Shocks ◽  
Ulf Wave ◽  
Field Fluctuations ◽  
Fourier Spectra ◽  
The Waves ◽  
Upstream Waves

<p>We study the interaction of upstream ultra-low frequency (ULF) waves with collisionless shocks by analyzing the outputs of eleven 2.5D local hybrid simulation models. Our simulated shocks have Alfvénic Mach numbers between 4.29-7.42 and their θ<sub>BN</sub> angles are 15º, 30º, 45º and 50º. Thus all are quasi-parallel or marginally quasi-perpendicular shocks. Upstream of all of the shocks the ULF wave foreshock develops. It is populated by transverse and compressive ULF magnetic field fluctuations that propagate upstream in the rest frame of upstream plasma. We show that the properties of the upstream waves reflect on the properties of the shock ripples. We also show that due to these ripples, as different portions of upstream waves reach the shocks, they encounter shock sections with different properties, such as the downstream magnetic field and the orientation of the local shock normals. This means that the waves are not simply transmitted into the downstream region but are heavily processed by the shocks. The identity of upstream fluctuations is largely lost, since the downstream fluctuations do not resemble the upstream waves in their shape, waveform extension, orientation nor in their wavelength. However some features are conserved. For example, the Fourier spectra of upstream waves present a bump or flattening at wavelengths corresponding to those of the upstream ULF waves. Most of the corresponding compressive downstream spectra also exhibit these features, while transverse downstream spectra are largely featureless.</p>

scholarly journals Thin current sheets and the associated wave activity observed by Solar Orbiter

2021 ◽  
Author(s):  
Daniel Graham ◽  
Yuri Khotyaintsev ◽  
Konrad Steinvall ◽  
Andris Vaivads ◽  
Milan Maksimovic ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Plasma Waves ◽  
Wave Activity ◽  
Number Density ◽  
Current Sheets ◽  
Field Fluctuations ◽  
Density Perturbations ◽  
The Waves ◽  
The Magnetic Field

<p>Thin current sheets are routinely observed in the solar wind. Here we report observations of thin current sheets and the associated plasma waves using the Solar Orbiter spacecraft. The Radio and Plasma Waves (RPW) instrument provides high-resolution measurements of the electric field, number density perturbations, and magnetic field fluctuations, which we use to identify and characterise the observed waves, while the magnetic field provided by the MAG instrument is used to characterise the current sheets. We discuss the role of current sheets in the generation of the observed waves and the effects of the waves on the current sheets.<span> </span></p>

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