Relationship between the Pi2 pulsations and the localized impulsive current associated with the current disruption in the magnetosphere

Fujita, Shigeru; Itonaga, M.; Nakata, Hiroyuki

doi:10.1186/bf03351636

Cited by 25 publications

(32 citation statements)

References 27 publications

(62 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…3 except for the period of 1538-1558 UT on January 4, 1997. may be considered as another candidate. The plasmapause is thought to be a non-perfect reflector for the fast mode waves, leading to leakage of the wave energy to the plasma trough (Fujita and Glassmeier, 1995;Lee and Lysak, 1999;Fujita et al, 2000Fujita et al, , 2002. If the condition of the plasmapause is different between the nightside and the dayside, the reflection (and transmission) rate of the fast mode waves at the plasmapause is expected to be different and may give rise to the phase shift between the nightside and the dayside.…”

Section: Discussionmentioning

confidence: 99%

Longitudinal dependence of characteristics of low-latitude Pi2 pulsations observed at Kakioka and Hermanus

2006

View full text Add to dashboard Cite

We statistically investigated longitudinal dependence of characteristics of low-latitude Pi2 pulsations to find the longitudinal structure of the plasmaspheric cavity mode. We used the geomagnetic field data from two ground stations, Kakioka (27.2• geomagnetic latitude, 208.5• geomagnetic longitude) and Hermanus (−33.9• geomagnetic latitude, 82.2• geomagnetic longitude), and auroral image data acquired by the ultraviolet imager onboard the Polar satellite for the period of December 4, 1996 to March 3, 1997. Our findings include the following: (1) Pi2 amplitude is the largest around the magnetic local time of the auroral breakup site and decreases away from it; (2) when a nightside Pi2 pulsation has large amplitude, a dayside Pi2 pulsation can be observed with a similar waveform; (3) Pi2 pulsations generally have no clear phase differences (mean phase difference of 3.3• ) between Kakioka and Hermanus, except for some events; and (4) the phase difference is independent on MLT (difference of magnetic local time between a station and the auroral breakup). These observations suggest that the plasmaspheric cavity mode can be excited globally with a very small value of the azimuthal wave number (m ≈ 0).

show abstract

Section: Discussionmentioning

confidence: 99%

Longitudinal dependence of characteristics of low-latitude Pi2 pulsations observed at Kakioka and Hermanus

2006

View full text Add to dashboard Cite

show abstract

“…They are also similar to those of two power peaks in the virtual plasmaspheric resonances solved by Lee (1998) with an analytical box model. However, Fujita et al (2000) recently studied the transient response of impulse source in the realistic magnetosphere model. Their results show that the electric field of the fundamental mode does not have a node at the plasmapause.…”

Section: Discussion and Summarymentioning

confidence: 99%

Spectral power of low-latitude Pi 2 pulsations at the 210° magnetic meridian stations and plasmaspheric cavity resonances

2014

View full text Add to dashboard Cite

Pi 2 pulsations at low latitudes are examined with magnetic fields data at the 210• magnetic meridian (MM) stations in 1991. Due to high degree of coherence over most latitudes, 68 low-latitude Pi 2 events at the 210• MM stations are identified with reference to same waveforms on the magnetogram at Lunping (189.5• MM, L = 1.06). With spectral power analysis, the ratio of the first four harmonic frequencies of low-latitude Pi 2 pulsations is about 1 : (1.7 ± 0.1) : (2.3 ± 0.1) : (2.9 ± 0.1). By using a box model for the inner magnetosphere, the cold linearized MHD wave equations are studied with realistic Alfven speed profile for nonuniform ambient magnetic fields. With appropriate parameters to depict the magnetospheric environments during the aforementioned period, numerical results are acquired with the fourth order Runge-Kutta method. It is found that the ratio of the first four harmonic frequencies of plasmaspheric cavity resonances is about 1 : 1.7 : 2.4 : 3.1 that is consistent with data analysis. This suggests that low-latitude Pi 2 pulsations at the 210• MM stations may be plasmaspheric cavity resonances driven by fast compressional waves owing to the impulsive source at the magnetotail.

show abstract

“…The magnetosphere model is essentially the same as that used by Fujita et al (2000) except that the equatorial VA is calculated using the plasma density model presented by Pekrides et al (1997) We also check invariance of the results by using several values of the time step (At).…”

Section: Model and Basic Equationsmentioning

confidence: 99%

Propagation property of transient MHD impulses in the Magnetosphere‐Ionosphere System: The 2D model of the Pi2 pulsation

Fujita

Mizuta²,

Itonaga

et al. 2001

Geophysical Research Letters

Self Cite

View full text Add to dashboard Cite

Abstract.Propagation property of the 2D-coupled MHD wave induced from an impulsive current is studied by using a magnetospheric model having the dipole magnetic field, the ionosphere with Pedersen conductivity, and a free outer boundary. This study is the first step toward realistic modeling of Pi2 pulsation generated by the current wedge model. Numerical calculation reveals that the ionosphere controls not only damping of the field-line resonance oscillation but also its frequency. The field-line resonance oscillation exhibits the fundamental mode structure along the field line in the plasmasphere. In high latitudes, there are waves bouncing between the ionospheres. This suggests that the waveform in the middle-and low-latitudes is different

show abstract

Relationship between the Pi2 pulsations and the localized impulsive current associated with the current disruption in the magnetosphere

Cited by 25 publications

References 27 publications

Longitudinal dependence of characteristics of low-latitude Pi2 pulsations observed at Kakioka and Hermanus

Longitudinal dependence of characteristics of low-latitude Pi2 pulsations observed at Kakioka and Hermanus

Spectral power of low-latitude Pi 2 pulsations at the 210° magnetic meridian stations and plasmaspheric cavity resonances

Propagation property of transient MHD impulses in the Magnetosphere‐Ionosphere System: The 2D model of the Pi2 pulsation

Contact Info

Product

Resources

About