Global aurora dynamics campaign, 1985-1986.

Abstract

Outline of the Global Aurora Dynamics Campaign, carried out from December 20, 1985 to February 3, 1986, is briefly described. Some of the initial results are reviewed in connection with other campaign papers of this issue. Importance and effectiveness of multi-station network observation are emphasized for obtaining spatio-temporal information of the upper atmosphere phenomena such as auroral activities and magnetic field perturbations. The network observation is useful especially for studying the global propagation of ULF waves, global dynamics of auroras, and consistent relationships among electric currents, conductivity distributions and electric fields. It is shown that the multi-station network is also greatly efficient to increase the possibilities of studying the relationships between in situ measurements of the magnetospheric plasma parameters by satellites and ground observations of precipitation particles and field variations along the common magnetic field lines. I. IntroductionDirect measurements of plasma parameters using satellites have an essential weakness in distinguishing temporal variations from spatial changes, although crucial in the study of the ionosphere-magnetosphere plasma properties. This drawback can be effectively compensated with coordinated ground network observations of particle precipitations and electromagnetic field variations. Ground-based multi-station observations provide us with two-dimensional, spatial and temporal information, although this kind of information is, more or less, indirect because what we observe are the relevant phenomena at the ionospheric level or on the ground propagated down from the magnetosphere. The ground multi-station observations also efficiently increase the possibility of satellite-ground comparison. Examination of models and subsequent decisive conclusion on many problems of the ionosphere-magnetosphere physics could be obtained only by comparing in situ measurements of plasma parameters by satellite with ground-based observations along the common field lines.The global aurora dynamics campaign was carried out during the period from December 20, 1985 to February 3, 1986. The purpose of this campaign is the study of 1) global dynamics of aurora, 2) generation and propagation of ULF-VLF waves in 485 486T. OGUTI et al. connection with auroral activities, 3) relationships between observations on the ground and those in the magnetosphere by satellites, 4) the energetics in the ionosphere-magnetosphere coupling system including wave-particle interactions, and 5) propagation of ULF waves on the global scale whether they are related to auroral activities or not.The campaign was organized by

Particle and field signatures during pseudobreakup and major expansion onset

“…This requirement includes the need for detailed information on the relationship between ionospheric disturbances and the related magnetospheric disturbances. We present two typical onset sequences observed from ground-based and satellite facilities, which took place at 0251 UT on January 2 and at 0006 UT on January 8, 1986, during the Global Auroral Dynamics Campaign 1985/1986 [Oguti et al, 1988a] and the 1985/1986 South Pole Balloon Campaign [Bering et al, 1987]. A number of magnetometers and two all-sky TV cameras were operated, which gave information on the substorm temporal and spatial evolution.…”

A plasma bulk motion in the midnight magnetosphere during auroral breakup inferred from all-sky image and magnetic field observations at geosynchronous altitudes

“…When foot points of satellites were projected on the ionosphere, the eastern satellite (GOES5) was 13.71 east of the TV station and the western satellite (GOES6) was 7.41 west. Observations using such unique ground-satellite distributions were made during the period of Global Aurora Dynamics Campaign (January 1-31, 1986) (Oguti et al, 1988). We surveyed both the aurora and ground Pi2 data during GADC periods.…”

Excitation of the third harmonic mode in meridian planes for Pi2 in the auroral zone

“…The footprints in the T89 model [ Tsyganenko , 1989] are (54.9 N, 281.4) for Kp = 0 in geographic coordinates. We examined three events during the Global Aurora Dynamics Campaign [ Oguti et al , 1988]. The onsets of these events were 0444 UT (23.6 MLT at GWR) for the 24 January event, 0501 UT (23.9 MLT) for the 27 January event, and 0517 UT (0.2 M LT) for the 30 January event.…”