A whistler is a very low frequency (VLF) phenomenon that acquires its characteristics from dispersive propagation in the magnetosphere. Whistlers are derived from the intense VLF radiation produced in lightning strikes. which can travel great distances within the Earth-ionosphere waveguide (EIWG) before penetrating the ionosphere. and exciting a duct. https://fitnessgravesyardes.shop/product-category/book-rack/