scholarly journals Magnetopause oscillations near the planetary period at Saturn: Occurrence, phase, and amplitude

2010 ◽  
Vol 115 (A8) ◽  
pp. n/a-n/a ◽  
Author(s):  
K. E. Clarke ◽  
D. J. Andrews ◽  
C. S. Arridge ◽  
A. J. Coates ◽  
S. W. H. Cowley
Keyword(s):  
Magnetopause Oscillations

scholarly journals MHD-waves in the geomagnetic tail: A review

10.12737/7168 ◽  
2015 ◽  
Vol 1 (1) ◽  
pp. 4-22 ◽  
Author(s):  
Анатолий Леонович ◽  
Anatoliy Leonovich ◽  
Виталий Мазур ◽  
Vitaliy Mazur ◽  
Даниил Козлов ◽  
...  
Keyword(s):  
Numerical Models ◽  
Experimental Studies ◽  
Low Frequency ◽  
Detailed Comparison ◽  
Mhd Waves ◽  
Theoretical Studies ◽  
Geomagnetic Tail ◽  
Magnetopause Oscillations ◽  
Experimental And Theoretical Studies ◽  
Theoretical Results

This article presents the review of experimental and theoretical studies on ultra-low-frequency MHD oscillations of the geomagnetic tail. We consider the Kelvin–Helmholtz instability at the magnetopause, oscillations with a discrete spectrum in the “magic frequencies” range, the ballooning instability of coupled Alfvén and slow magnetosonic waves, and “flapping” oscillations of the current sheet of the geomagnetic tail. Over the last decade, observations from THEMIS, CLUSTER and Double Star satellites have been of great importance for experimental studies. The use of several spacecraft allows us to study the structure of MHD oscillations with high spatial resolution. Due to this, we can make a detailed comparison between theoretical results and those obtained from multi-spacecraft studies. To make such comparisons in theoretical studies, in turn, we have to use the numerical models closest to the real magnetosphere.

scholarly journals Coordinated polar spacecraft, geosynchronous spacecraft, and ground-based observations of magnetopause processes and their coupling to the ionosphere

2004 ◽  
Vol 22 (12) ◽  
pp. 4329-4350 ◽  
Author(s):  
G. Le ◽  
S.-H. Chen ◽  
Y. Zheng ◽  
C. T. Russell ◽  
J. A. Slavin ◽  
...  
Keyword(s):  
Solar Wind ◽  
High Speed ◽  
Reconnection Rate ◽  
Flux Transfer Events ◽  
Speed Solar Wind ◽  
Flux Transfer ◽  
Field Lines ◽  
Magnetopause Oscillations ◽  
High Speed Solar Wind

Abstract. In this paper, we present in-situ observations of processes occurring at the magnetopause and vicinity, including surface waves, oscillatory magnetospheric field lines, and flux transfer events, and coordinated observations at geosynchronous orbit by the GOES spacecraft, and on the ground by CANOPUS and 210° Magnetic Meridian (210MM) magnetometer arrays. On 7 February 2002, during a high-speed solar wind stream, the Polar spacecraft was skimming the magnetopause in a post-noon meridian plane for ~3h. During this interval, it made two short excursions and a few partial crossings into the magnetosheath and observed quasi-periodic cold ion bursts in the region adjacent to the magnetopause current layer. The multiple magnetopause crossings, as well as the velocity of the cold ion bursts, indicate that the magnetopause was oscillating with an ~6-min period. Simultaneous observations of Pc5 waves at geosynchronous orbit by the GOES spacecraft and on the ground by the CANOPUS magnetometer array reveal that these magnetospheric pulsations were forced oscillations of magnetic field lines directly driven by the magnetopause oscillations. The magnetospheric pulsations occurred only in a limited longitudinal region in the post-noon dayside sector, and were not a global phenomenon, as one would expect for global field line resonance. Thus, the magnetopause oscillations at the source were also limited to a localized region spanning ~4h in local time. These observations suggest that it is unlikely that the Kelvin-Helmholz instability and/or fluctuations in the solar wind dynamic pressure were the direct driving mechanisms for the observed boundary oscillations. Instead, the likely mechanism for the localized boundary oscillations was pulsed reconnection at the magnetopause occurring along the X-line extending over the same 4-h region. The Pc5 band pressure fluctuations commonly seen in high-speed solar wind streams may modulate the reconnection rate as an indirect cause of the observed Pc5 pulsations. During the same interval, two flux transfer events were also observed in the magnetosphere near the oscillating magnetopause. Their ground signatures were identified in the CANOPUS data. The time delays of the FTE signatures from the Polar spacecraft to the ground stations enable us to estimate that the longitudinal extent of the reconnection X-line at the magnetopause was ~43° or ~5.2 RE. The coordinated in-situ and ground-based observations suggest that FTEs are produced by transient reconnection taking place along a single extended X-line at the magnetopause, as suggested in the models by Scholer (1988) and Southwood et al. (1988). The observations from this study suggest that the reconnection occurred in two different forms simultaneously in the same general region at the dayside magnetopause: 1) continuous reconnection with a pulsed reconnection rate, and 2) transient reconnection as flux transfer events. Key words. Magnetospheric physics (Magnetopause, cusp and boundary layers; Magnetosphere-ionosphere interactions; MHD waves and instabilities)

INTERBALL tail observations of dayside magnetopause oscillations and simultaneous POLAR cusp measurements

1999 ◽  
Vol 26 (7) ◽  
pp. 963-966 ◽  
Author(s):  
D. L. Dempsey ◽  
L. A. Avanov ◽  
J. H. Waite ◽  
O. L. Vaisberg ◽  
J. L. Burch ◽  
...  
Keyword(s):  
Polar Cusp ◽  
Dayside Magnetopause ◽  
Magnetopause Oscillations

scholarly journals Long-period geomagnetic pulsations caused by the solar wind negative pressure impulse on 22 March 1979 (CDAW-6)

1998 ◽  
Vol 16 (2) ◽  
pp. 134-139 ◽  
Author(s):  
V. A. Parkhomov ◽  
V. V. Mishin ◽  
L. V. Borovik
Keyword(s):  
Solar Wind ◽  
Oscillation Period ◽  
Time Interval ◽  
Geomagnetic Pulsations ◽  
Resonance Mechanism ◽  
Long Period ◽  
Latitudinal Dependence ◽  
Abrupt Contraction ◽  
Magnetopause Oscillations ◽  
Latitudinal Range

Abstract. An analysis is made of the long-period geomagnetic pulsations as recorded at seven Norilsk meridian stations (λ=162°, latitudinal range: 61°–71°N) following abrupt magnetospheric expansion during the storm of 22 March 1979 caused by a rapid decrease in solar wind density. As with the time interval following an abrupt contraction at the time of sudden storm commencement, there exist two types of pulsations in the pulsation spectra: latitude-independent  (T>400 s) and latitude-dependent (T<200 s) pulsations. The first pulsation type is interpreted in terms of forced pulsations associated with magnetopause oscillations. The oscillation period is determined by plasma density in the boundary layer and by the radius of the magnetosphere (T ~ ρ1/2R4). The latitudinal dependence of the period, amplitude and polarization of the second-type pulsations is in agreement with the resonance mechanism of their origin.Keywords. Geomagnetic pulsations · Solar wind · Magnetopause oscillations

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