简介：

简介：Generationofzonalflowsbysmall-scaledrift-Alfvenmodesisinvestigatedbyadoptingtheapproachofparametricinstabilitywiththeelectronpolarizationdriftincluded.Thezonalmodecanbeexcitedbyprimarymodespropagatingatbothelectronandiondiamagneticdriftdirectionsincontrasttotheassertioninpreviousstudiesthatonlyprimarymodespropagatingintheiondiamagneticdriftdirectionscandrivezonalinstabilities.Generally,thegrowthrateofthedrivenzonalmodeisinthesameorderasthatinpreviousstudy.However,differentfromthepreviouswork,thegrowthrateisnolongerproportionaltothedifferencebetweenthediamagneticdriftfrequenciesofelectronsandions.

简介：TimeevolutionofionosphericD-regionplasmasincludingtheperturbationsofelectronsandchargedaerosolparticlesisinvestigatedundertheconditionsofpolarmesospheresummerechoes(PMSE).ItisshownthatthetimescaleofdecayoftheelectrondensityisintheorderofanhourundertypicalPMSEconditions,inthemajorityofcases,theelectrondensityisanticorrelatedtotheiondensity,exceptthattheradiusofaerosolparticlesisgreaterthan50nm.Also,theevolutionsundervariedparameters,suchastheamplitudeandwidthofperturbation,theaerosolparticleradius,andthealtitudeofthePMSEoccurrenceareinvestigated.Theobtainedresultsareusefulforinterpretingtheexperimentalobservations.