An incoherent scatter radar measurement of the average ion mass and temperature of a nighttime sporadic layer

We report the results of incoherent scatter radar, total power, and ion line observations of a nighttime sporadic layer centered at 92-km altitude. The height variation of the absolute widths of the ion line yields a layer temperature of 210/sup 0/ +- 5 /sup 0/K and a mean ion mass of 50 +- 10 amu. This ion mass, when compared with average meteor composition, indicates that the layer is composed totally of metallic ions.