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A Pi2-associated dusk-to-dawn currents in the midnight sector as observed at L = 6.6 during multiple Pi2 onsets
Earth, Planets and Space volume 56, pages 663–668 (2004)
We examined the magnetic fields and energetic particle data from geosynchronous satellites GOES 6 and S/C1984-129 during the multiple onset of Pi2. We found that the energetic particle injection in the midnight sector was associated with the consecutive Pi2 onset. The magnetometer on board GOES 6 at the midnight sector detected the increase of the field inclination as well as a decrease of the field magnitudes during the Pi2 events. We suggest that such a field reconfiguration could be provoked by the formation of the dusk-to-dawn currents in the vicinity of the geosynchronous altitudes. The present study supports the Pi2 model that the impulsive dusk-to-dawn current and field-aligned current diverted from it are a source of Pi2 pulsation in the midnight magnetosphere.
Akasofu, S.-I., The development of auroral substorm, Planet. Space Sci., 12, 273–282, 1964.
Baker, D. N. et al., Neutral line model of substorms: Past results and present view, J. Geophys. Res., 101, 12975–13010, 1996.
Fujita, S., M. Itonaga, and N. Nakata. Relation between the Pi2 pulsations and the localized impulsive current associated with the current disruption in the magnetosphere, Earth Planets Space, 52, 267–281, 2000.
Fujita, S., H. Nakata, M. Itonaga, A. Yoshikawa, and T. Mizuta. A numerical simulation of the Pi2 pulsations associated with the substorm current wedge, J. Geophys. Res., 107, SMP2-1-2-15, 2002.
Lui, A. T. Y., K. Liou, M. Nose, S. Ohtani, D. Williams, T. Mukai, K. Tsuruda, and S. Kokubun, Near-Earth dipolarization: evidence for a non-MHD process, Geophys. Res. Lett., 26, 2905–2908, 1999.
Olson, J. V., Pi2 pulsations and substorm onsets: A review, J. Geophys. Res., 104, 17499–17520, 1999.
Reeves, G. D., T. A. Fritz, T. E. Cayton, and R. D. Belian, Multi-satellite measurements of the substorm injection region, Geophys. Res. Lett., 17, 2015–2018, 1990.
Saka, O., H. Akaki, O. Watanabe, and D. N. Baker, Ground-satellite correlation of low-latitude Pi2 pulsations: A quasi-periodic field line oscillation in the magnetosphere, J. Geophys. Res., 101, 15433–15440, 1996.
Saka, O., K. Okada, O. Watanabe, D. N. Baker, G. D. Reeves, and R. D. Belian, Pi2-associated particle flux and magnetic field modulations in geosynchronous altitudes, J. Geophys. Res., 102, 11363–11373, 1997.
Sakurai, T. and R. L. McPherron, Satellite observations of Pi2 activity at geosynchronous orbit, J. Geophys. Res., 88, 7015–7027, 1983.
Shiokawa, K., W. Baumjohann, and G. Haerendel, Braking of high-speed flows in the near-Earth tail, Geophys. Res. Lett., 24, 1179–1182, 1997.
Takahashi, K., S-I. Ohtani, and K. Yumoto, AMPTE CCE observations of Pi2 pulsations in the inner magnetosphere, Geophys. Res. Lett., 19, 1447–1450, 1992.
Takahashi, K., S-I. Ohtani, and B. J. Anderson, Statistical analysis of Pi2 pulsations observed by the AMPTE CCE spacecraft in the inner magnetosphere, J. Geophys. Res., 100, 21929–21941, 1995.
Takahashi, K., B. J. Anderson, and S-I. Ohtani, Multisatellite study of night-side transient toroidal waves, J. Geophys. Res., 101, 24815–24825, 1996.
Yeoman, T. K. et al., A comparison of midlatitude Pi2 pulsations and geostationary orbit particle injections as substorm indicators, J. Geophys., Res., 99, 4085–4094, 1994.
Yumoto, K., et al., Some aspects of the relation between Pi1–2 magnetic pulsations observed at L = 1.3–2.1 on the ground and substorm-associated magnetic field variations in the near-Earth magnetotail observed by AMPTE CCE, J. Geophys. Res., 94, 3611–3618, 1989.
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Saka, O., Akaki, H. & Baker, D.N. A Pi2-associated dusk-to-dawn currents in the midnight sector as observed at L = 6.6 during multiple Pi2 onsets. Earth Planet Sp 56, 663–668 (2004). https://doi.org/10.1186/BF03352528
- Magnetospheric substorm
- Pi2 onset
- plasma dynamics
- geosynchronous altitudes