The Auroral Turbulence 2 (AT2) rocked was launched on February 11, 1997 from Poker Flat, Alaska. The rocket had three separated payloads (Main, North and East). Each payload was carrying a fluxgate magnetometer, a double probe electric field instrument and a particle detector. The AT2 reached an apogee of about 500 km. Just before apogee, AT2 crossed an intense auroral arc with a small relative velocity of 0.3 km/sec transverse to the arc.
An electron acceleration
event similar to the one described in the previous section was observed by
AT2 at the edge of the
arc (see Figure 1 in [14,15]). Payloads separated by 3 km
observe an Alfvénic activity at 0.5 Hz
with electric and magnetic field oscillations almost in phase.
On the other hand the detection of the envelope of these
oscillations was clearly shifted in time between the payloads. This means
the payloads were
crossing a spatially localized region of temporal oscillations.
The estimated width of the region was about 4 km which is much larger than
the electron inertial length
m.
Field aligned dispersive electron precipitations were observed
simultaneously on all payloads and appear to be in phase
with Alfvénic fluctuations.