Plasma diagnostics with Langmuir probes in the equatorial ionosphere: II. Evaluation of DEOS flight F06

The Right data of an ionospheric sounding rocket (DEOS campaign flight F06) are evaluated with respect to electron density and temperature profiles. T he probe characteristic is analysed in the frame of a model that takes the influence of the geomagnetic field and of a contamination layer into accoun t, as described in part I (Piel et al 2001 J. Phys. D: Appl Phys.). The ele ctron temperature of the night-time ionosphere is found to be higher (1300 K) than that predicted by the IRI-95 model (Bilitza D 1999 J. Atmos. Terr P hys. 61 167), but in general agreement with the model of Watanabe et al (Wa tanabe et al 1995 J. Geophys. Res. 100 14 581). It is also found that the e lectron temperature in depleted plasma regions (plasma bubbles) is lower th an in the unperturbed plasma. This is a hint at the action of the Rayleigh- Taylor mechanism that convects cold low-density plasma from the bottomside of the F-layer to higher altitudes inside the plasma bubbles. An absolute c omparison of the electron density profiles from the analysis of the Langmui r probe and by an independent impedance probe is performed. Excellent agree ment of the profile shape and of absolute density values can be achieved ov er the entire altitude regime.. It is demonstrated which steps in the evalu ation procedure of the probe characteristic may lead to systematic errors i n electron density.