简介：Followingabriefhistoryandprogressofionosphericresearch,thispaperpresentsabriefreviewoftherecentdevelopmentsintheunderstandingoftwomajorphenomenainlowandmidlatitudeionosphere—theequatorialionizationanomaly(EIA)andinvolvedequatorialplasmafountain(EPF)andionosphericirregularities.Unliketheeasy-to-understandmisinterpretations,theEPFinvolvesfieldperpendicularE×Bplasmadriftandfield-alignedplasmadiffusionactingtogetherandplasmaflowinginthedirectionoftheresultantatallpointsalongthefieldlinesatallaltitudes.TheEIAisformedmainlyfromtheremovalofplasmafromaroundtheequatorbytheupwardE×Bdriftcreatingthetroughandconsequentlythecrestswithsmallaccumulationofplasmaatthecrestswhenthecrestsarewithin~±20°magneticlatitudesandnoaccumulationwhentheyarebeyond~±25°magneticlatitudes.ThestrongEIAundermagneticallyactiveconditionsarisesfromthesimultaneousimpulsiveactionofeastwardpromptpenetrationelectricfieldandequatorwardneutralwind.Intenseionosphericirregularitiesdevelopinthepost-sunsetbottom-sideequatorialionospherewhenitrisestohighaltitudes,andevolvenonlinearlyintothetopside.Pre-reversalenhancement(PRE)oftheverticalupwardE×BdriftanditsfluctuationsamplifiedduringPREprovidethedrivingforceandseed,withneutralwindandgravitywavesbeingtheprimarysources.AtlowsolaractivityespeciallyinsummerwhenfastvaryingPREisabsent,theslowvaryinggravitywavesincludinglargescalewaves(LSW)seemtoactasbothdriverandseedforweakirregularities.Atmidlatitudes,theirregularitiesareweakandassociatedwithmediumscaletravelingionosphericdisturbances(MSTIDs).AlowlatitudeminimumintheoccurrenceoftheirregularitiesatMarchequinoxpredictedbytheoreticalmodelsisidentified.TheminimumoccursonthepolewardsideoftheEIAcrestandshiftsequatorwardfrom~25°magneticlatitudesathighsolaractivitytobelow17°atlowsolaractivity