High-frequency coherent plasma waves observed in the lower auroral ionosphere

Probe measurements of plasma irregularities in the lower E region during an auroral event showed the presence of coherent wave forms with a wavelength extending down to 35 cm that can be explained by the Farley-Buneman instability. Our results can be interpreted in the frame of recent theories of electron heating by unstable waves. Our data provide experimental evidence that coherent short-wavelength waves can be excited as is assumed in these theories. The measurements were made from rocket AAD-VIIIC-09 (ARIES-A) that formed part of the ARIES campaign for auroral modelling. A partir de mesures par sondes Clectrostatiques dans la region E infkrieure durant une aurore, on a pu mettre en Cvidence des irrkgularites de plasma dues a des ondes cohirentes dont la longueur d'onde peut Ctre aussi courte que 35 cm et qui semblent avoir pour origine I'instabilitC Farley-Buneman. Les resultats peuvent &tre interpret& dans le cadre de rCcentes thtories du chauffage Clectronique par des ondes instables. L'ensemble des donnees constitue une Cvidence experimentale de I'excitation de fluctuations de courte longueur d'onde, I'hypothkse fondamentale de ces theories. Les mesures ont CtC rCalisCes a bord de la fusee AAD-VIlIC-09 (ARIES-A), pendant la campagne de rnodClisation aurorale ARIES. Can. J. Phys. 69, 941 (1991)