短語詞組短語helical flow field 螺鏇流場helical magnetic field 螺鏇磁場spatially periodic helical magnetic field 周期性磁場poloidal helical field 垂環(huán)螺鏇場resonant helical field 共振螺鏇場transverse helical wiggle magnetic field 橫曏螺鏇搖擺磁場helical coil steam generator field 螺鏇場 返回 helical field