IMAGES OF TRANSEQUATORIAL F-REGION BUBBLES IN 630 AND 777-NM EMISSIONS COMPARED WITH SATELLITE MEASUREMENTS

Images of transequatorial F region bubbles were obtained from magnetic field aligned airglow observations from Haleakala, Hawaii, for 9 nigh ts in August 1988. Bubbles of scale size 10-100 km were recorded with an intensified CCD detector attached to a filter wheel imager, and seq uential images were made in the plasma recombination emissions at 630 nm and 777 nm and in the background emissions. The observations also y ield information on the large-scale structure of the ionosphere in the northern Appleton Anomaly region, particularly on the latitude variat ions of plasma concentration and layer height. Measurements from the D MSP F8 and F9 satellites extend this to include the southern Anomaly r egion. The DMSP satellites were near 830 km in altitude and in near-po lar orbits at about 1800 and 2120 hours local time. A comparison of th e bubble images and the DMSP results with plasma concentration and dri ft velocities obtained from the San Marco satellite allows us to put t he measurements along the San Marco track into the larger ionospheric context. One-to-one correspondence is found between the presence of th e optical bubbles and the presence of plasma depletions measured from the San Marco satellite, allowing identification on consecutive orbits of the same depletions. This extends for up to 5 hours of the satelli te measured information for individual depletions, that is, their vert ical and horizontal drift velocities and the plasma concentration vari ations. The images show the shapes of the depletions in apex height an d longitude and their evolution. Horizontal drift velocities of the bu bbles were determined by a correlation analysis. Bubble occurrence is compared with day-to-day changes in the equatorial fountain electric f ields and transequatorial asymmetries caused by neutral winds, and wit h measurements of radar backscatter from centimeter-scale irregulariti es associated with bubbles in the Kwajalein sector. The development of 10-100 km scale size bubbles at a given time and location is clearly a consequence of the presence of even larger wavelike corrugations in the F layer, provided there is also at least a moderately strong equat orial fountain.