I believe I first encountered the work of Radigue when I was in grad school. Her works are massive yet also somewhat wraith-like. Large and spacious, but also intimate. You could call it ‘drone music’ if you wanted, but that misses the specificity and richness of her work. It’s about sound, duration, scale, corporeality, … As a first stop, I would recommend checking out the Trilogie de la Mort, but there are lots of other works for you to peruse.
If you would like a bit of background on her work before or while you listen, why not check out this interview in Frieze magazine. It covers her approach to space, her relation with Tibetan Buddhism, her recent turn from electroacoustics to acoustic instruments, among other aspects.