TY - JOUR T1 - Ducted compressional waves in the magnetosphere in the double-polytropic approximation JO - ANN GEOPHYS-GERMANY PY - 2002/10/01 AU - Ballai I AU - Erdelyi R AU - Roberts B ED - VL - 20 IS - 10 SP - 1553 EP - 1558 Y2 - 2024/12/22 ER -