摘要
Inthispaper,theobtainedexperimentalresultsconcerningcreationofbulkelementaryexcitations(BEEs)iniso-topicallypureliquid4Heatlowtemperatures~60mKarediscussed.Positiverotons’(R+-rotons)creationbyapulsedheaterwasstudied.Signalswererecordedforthefollowingquantumprocesses:quantumevaporationof4He-atomsfromthefreeliq-uid-heliumsurfacebytheBEEsoftheliquidhelium-II,andBEEsreflectionfromthefreesurfacebackintothebulkliquid.Typicalsignalsareshown,andratiosofsignalamplitudesareevaluated.Forlongheaterpulsesfrom5to10μs,appearanceofthesecondatomiccloudconsistingofevaporated4He-atomswasobservedinadditiontothefirstatomiccloud.Itisthoughtthatthefirstatomiccloudoftheevaporatedheliumatomsconsistsofveryfast4He-atomswithenergies~35Kevaporatedbypositiverotonswiththespecialenergies~17K(~2ER~2×8.6KwithERrepresentingtherotonminimumenergy)correspondingtothethirdnon-dispersiveZakharenkowave.Thesecondcloudofslower4He-atomswascreatedbysurfaceelementaryexcitations(SEEsorripplons)possessingthespecialenergies~7.15Krepresentingthebindingenergy.ItwasassumedthatsuchSEEscanbecreatedbyphononsincomingtotheliquidsurfacewithspecialenergies~6.2Kcorrespondingtothefirstnon-dispersiveZakharenkowave,whichcaninteractattheliquidsurfacewiththesamephononsalreadyreflectedfromthesurfaceforlongheaterpulses.Also,somepulsed-heatercharacteristicswerestudiedinordertobetterunderstandthefeaturesofsuchheatersinlowtemperatureexperi-ments.
出版日期
2007年07月17日（中国期刊网平台首次上网日期，不代表论文的发表时间）
