Abstract
The north-south asymmetry of the amplitude of ULF pulsations in the Pc 3-5 band is studied using magnetic field data from the magnetically conjugate stations at L ∼ 5.4: Kotzebue (KOT) in the northern hemisphere and Macquarie Island (MCQ) in the southern hemisphere. We obtained the following results for the northward (H) component of magnetic pulsations: (1) The north to south power ratio shows a maximum in the northern winter and a minimum in the northern summer. This "seasonal variation" is stronger at higher frequencies (Pc 3 and Pc 4 frequencies). (2) The north to south power ratio for the Pc 4 and Pc 5 frequency band is basically greater than 1.0 for all seasons. This "positive offset" is stronger at lower frequencies. The "seasonal variation" implies that the magnetohydrodynamic (MHD) waves incident from the magnetosphere are more strongly shielded when the ionospheric conductivity is higher. The "positive offset" may result from the difference of the background magnetic field intensity between KOT and MCQ.
| Original language | English |
|---|---|
| Article number | A10214 |
| Journal | Journal of Geophysical Research: Space Physics |
| Volume | 110 |
| Issue number | A10 |
| DOIs | |
| Publication status | Published - Jan 1 2005 |
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Cite this
North-south asymmetry of the amplitude of high-latitude Pc 3-5 pulsations : Observations at conjugate stations. / Obana, Yuki; Yoshikawa, Akimasa; Olson, John V.; Morris, Ray J.; Fraser, Brian J.; Yumoto, Kiyohumi.
In: Journal of Geophysical Research: Space Physics, Vol. 110, No. A10, A10214, 01.01.2005.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - North-south asymmetry of the amplitude of high-latitude Pc 3-5 pulsations
T2 - Observations at conjugate stations
AU - Obana, Yuki
AU - Yoshikawa, Akimasa
AU - Olson, John V.
AU - Morris, Ray J.
AU - Fraser, Brian J.
AU - Yumoto, Kiyohumi
PY - 2005/1/1
Y1 - 2005/1/1
N2 - The north-south asymmetry of the amplitude of ULF pulsations in the Pc 3-5 band is studied using magnetic field data from the magnetically conjugate stations at L ∼ 5.4: Kotzebue (KOT) in the northern hemisphere and Macquarie Island (MCQ) in the southern hemisphere. We obtained the following results for the northward (H) component of magnetic pulsations: (1) The north to south power ratio shows a maximum in the northern winter and a minimum in the northern summer. This "seasonal variation" is stronger at higher frequencies (Pc 3 and Pc 4 frequencies). (2) The north to south power ratio for the Pc 4 and Pc 5 frequency band is basically greater than 1.0 for all seasons. This "positive offset" is stronger at lower frequencies. The "seasonal variation" implies that the magnetohydrodynamic (MHD) waves incident from the magnetosphere are more strongly shielded when the ionospheric conductivity is higher. The "positive offset" may result from the difference of the background magnetic field intensity between KOT and MCQ.
AB - The north-south asymmetry of the amplitude of ULF pulsations in the Pc 3-5 band is studied using magnetic field data from the magnetically conjugate stations at L ∼ 5.4: Kotzebue (KOT) in the northern hemisphere and Macquarie Island (MCQ) in the southern hemisphere. We obtained the following results for the northward (H) component of magnetic pulsations: (1) The north to south power ratio shows a maximum in the northern winter and a minimum in the northern summer. This "seasonal variation" is stronger at higher frequencies (Pc 3 and Pc 4 frequencies). (2) The north to south power ratio for the Pc 4 and Pc 5 frequency band is basically greater than 1.0 for all seasons. This "positive offset" is stronger at lower frequencies. The "seasonal variation" implies that the magnetohydrodynamic (MHD) waves incident from the magnetosphere are more strongly shielded when the ionospheric conductivity is higher. The "positive offset" may result from the difference of the background magnetic field intensity between KOT and MCQ.
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U2 - 10.1029/2003JA010242
DO - 10.1029/2003JA010242
M3 - Article
AN - SCOPUS:33845798623
VL - 110
JO - Journal of Geophysical Research
JF - Journal of Geophysical Research
SN - 0148-0227
IS - A10
M1 - A10214
ER -