Session 8S - Space.
POSTER session, Thursday afternoon, November 14
Exhibit Hall - Concourse Level, Adam's Mark
A lidar system consisting of a 2.7 m diameter rotating mercury collector and a 7 mJ/pulse 10 Hz excimer pumped dye laser tuned to the Na-D_2 (589 nm), resonance, has been installed at the HIPAS Observatory, Alaska (65^\circN-147^\circW). The lidar passes under the electrojet and the aurora. It is inside an arctic building with a glass skylight for winter operation (\geq-40^\circ outside). During an auroral storm (3/18/96), we observed the formation of sporadic Na layers 30 km above the ``normal Na'' layer at 90 km altitude. It is proposed that, in this case, Na was released from compound reservoirs by earth captured solar protons, penetrating no further than 120 km altitudes,(F.Sigernes, et all, "Calculation and ground-based observations of pulsed proton events in the dayside aurora, J.Atmos. Terrs. Phys., 58, 1281-1291, 1996. ) and that a Na lidar is a new diagnostic for such events. Our lidar will include a ``Doubled flashlamp pumped Ti-sapphire laser'' (125 mJ/pulse at 10 Hz at 391.4 nm, the wavlength of the N2^+ bandhead). Work Supported by ONR N00014-91-C-0191.