### Abstract

The objective of this study is to understand better the propagation of Pi 2 waves in the nighttime region. We examined Pi 2 oscillations that showed high correlation between high- and low-latitude Magnetic Data Acquisition System/Circum Pan-Pacific Magnetometer Network stations (correlation coefficient: |γ| ≥ 0.75). For each horizontal component (H and D) we examined the magnetic local time (MLT) dependence of the delay time of high-latitude Pi 2 oscillations that corresponds to the highest correlation with the low-latitude Pi 2 oscillation. We found the delay time of the high-latitude H showed remarkable MLT dependence, especially in the premidnight sector: we found that in the premidnight sector the high-latitude H oscillation tends to delay from the low-latitude oscillation (<100 s). On the other hand, the delay time of the high-latitude D oscillation was not significant (∼±10 s) in the entire nighttime sector. We propose a Pi 2 propagation model to explain the observed delay time of high-correlation highlatitude H. The model quantitatively explains the trend of the event distribution. We also examined the spatial distribution of high-correlation Pi 2 events relative to the center of auroral breakups. It was found that the high-correlation Pi 2 events tend to occur away from the center of auroral breakups by more than 1.5 MLT. The present result suggests that the high-correlation H component Pi 2 oscillations at high latitude are a manifestation of forced Alfvén waves excited by fast magnetosonic waves.

Original language | English |
---|---|

Article number | A11207 |

Journal | Journal of Geophysical Research: Space Physics |

Volume | 114 |

Issue number | 11 |

DOIs | |

Publication status | Published - Nov 2009 |

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### All Science Journal Classification (ASJC) codes

- Geophysics
- Forestry
- Oceanography
- Aquatic Science
- Ecology
- Water Science and Technology
- Soil Science
- Geochemistry and Petrology
- Earth-Surface Processes
- Atmospheric Science
- Earth and Planetary Sciences (miscellaneous)
- Space and Planetary Science
- Palaeontology

### Cite this

*Journal of Geophysical Research: Space Physics*,

*114*(11), [A11207]. https://doi.org/10.1029/2009JA014163

**Propagation characteristics of Pi 2 pulsations observed at high- And low-latitude MAGDAS/CPMN stations : A statistical study.** / Uozumi, Teiji; Abe, S.; Kitamura, K.; Tokunaga, T.; Yoshikawa, A.; Kawano, H.; Marshall, R.; Morris, R. J.; Shevtsov, B. M.; Solovyev, S. I.; McNamara, D. J.; Liou, K.; Ohtani, S.; Itonaga, M.; Yumoto, K.

Research output: Contribution to journal › Article

*Journal of Geophysical Research: Space Physics*, vol. 114, no. 11, A11207. https://doi.org/10.1029/2009JA014163

}

TY - JOUR

T1 - Propagation characteristics of Pi 2 pulsations observed at high- And low-latitude MAGDAS/CPMN stations

T2 - A statistical study

AU - Uozumi, Teiji

AU - Abe, S.

AU - Kitamura, K.

AU - Tokunaga, T.

AU - Yoshikawa, A.

AU - Kawano, H.

AU - Marshall, R.

AU - Morris, R. J.

AU - Shevtsov, B. M.

AU - Solovyev, S. I.

AU - McNamara, D. J.

AU - Liou, K.

AU - Ohtani, S.

AU - Itonaga, M.

AU - Yumoto, K.

PY - 2009/11

Y1 - 2009/11

N2 - The objective of this study is to understand better the propagation of Pi 2 waves in the nighttime region. We examined Pi 2 oscillations that showed high correlation between high- and low-latitude Magnetic Data Acquisition System/Circum Pan-Pacific Magnetometer Network stations (correlation coefficient: |γ| ≥ 0.75). For each horizontal component (H and D) we examined the magnetic local time (MLT) dependence of the delay time of high-latitude Pi 2 oscillations that corresponds to the highest correlation with the low-latitude Pi 2 oscillation. We found the delay time of the high-latitude H showed remarkable MLT dependence, especially in the premidnight sector: we found that in the premidnight sector the high-latitude H oscillation tends to delay from the low-latitude oscillation (<100 s). On the other hand, the delay time of the high-latitude D oscillation was not significant (∼±10 s) in the entire nighttime sector. We propose a Pi 2 propagation model to explain the observed delay time of high-correlation highlatitude H. The model quantitatively explains the trend of the event distribution. We also examined the spatial distribution of high-correlation Pi 2 events relative to the center of auroral breakups. It was found that the high-correlation Pi 2 events tend to occur away from the center of auroral breakups by more than 1.5 MLT. The present result suggests that the high-correlation H component Pi 2 oscillations at high latitude are a manifestation of forced Alfvén waves excited by fast magnetosonic waves.

AB - The objective of this study is to understand better the propagation of Pi 2 waves in the nighttime region. We examined Pi 2 oscillations that showed high correlation between high- and low-latitude Magnetic Data Acquisition System/Circum Pan-Pacific Magnetometer Network stations (correlation coefficient: |γ| ≥ 0.75). For each horizontal component (H and D) we examined the magnetic local time (MLT) dependence of the delay time of high-latitude Pi 2 oscillations that corresponds to the highest correlation with the low-latitude Pi 2 oscillation. We found the delay time of the high-latitude H showed remarkable MLT dependence, especially in the premidnight sector: we found that in the premidnight sector the high-latitude H oscillation tends to delay from the low-latitude oscillation (<100 s). On the other hand, the delay time of the high-latitude D oscillation was not significant (∼±10 s) in the entire nighttime sector. We propose a Pi 2 propagation model to explain the observed delay time of high-correlation highlatitude H. The model quantitatively explains the trend of the event distribution. We also examined the spatial distribution of high-correlation Pi 2 events relative to the center of auroral breakups. It was found that the high-correlation Pi 2 events tend to occur away from the center of auroral breakups by more than 1.5 MLT. The present result suggests that the high-correlation H component Pi 2 oscillations at high latitude are a manifestation of forced Alfvén waves excited by fast magnetosonic waves.

UR - http://www.scopus.com/inward/record.url?scp=72149099064&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=72149099064&partnerID=8YFLogxK

U2 - 10.1029/2009JA014163

DO - 10.1029/2009JA014163

M3 - Article

AN - SCOPUS:72149099064

VL - 114

JO - Journal of Geophysical Research

JF - Journal of Geophysical Research

SN - 0148-0227

IS - 11

M1 - A11207

ER -