Abstract. Theexperimental andtheoretical development of ion cyclotronradofrequency heating (ICRF)intoroidalmagnetically-confined plasmasrecentlyculminatedwith the demonstration of ICRFheatingof D-Tplasmas, firstin theTokamakFusionTestReactor(TFTR)and then in the Joint EuropeanTorus (JET). Variousheating schemesbased on the cyclotronresonances betweentheplasmaionsandtheappliedICRFwaveshavebeenused,includingsecondharmonic tritium, minoritydeuterium, minorityhelium-3,modeconversionat the D-T ion-ion hybrid layer,andandionBernstein waveheating. Secondharmonictritium heatingwasfirst shownto be effectivein a reactor-grade plasmain TFTR. D-minorityheatingon JET has led to the achievement of Q = 0.22,theratioof fusionpowerproducedto RFpowerinput,sustainedovera few energyconfinementtimes. In this paper, some of the key building blocks in the development ofrf heatingofplasmasarereviewedandprospectsfor the development of advanced methodsof plasmacontrolbasedontheapplication ofrf wavesarediscussed.

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