At http://spaceweather.com 23rd November 2018 … musical waves in Earth's magnetic field (see also https://wattsupwiththat.com/2018/11/23/our-quiet-sun-produces-musical-wa…) … our quiet Sun produces musical waves in Earth's magnetic field. A space weather observatory in Norway (above the Arctic Circle) has this week detected sine waves of exceptional purity rippling through Earth's polar magnetic field. For some reason the comments at the second link are not exactly impressed – but you can't please everyone. The waves persisted for hours with near perfect pitch. They have been explained as explosions in Earth's magnetic tail – buffeted by the solar wind – in this case a mild coronal hole rather than a sun spot, (which are currently in short supply). Normally, magnetometers around the Arctic Circle go berserk when the solar wind arrives but on November 18th they created a pure almost musical sine wave.
A while ago a quartet of NASA spacecraft flew through just such an explosion, assumed to be a magnetic reconnection event, as they were orbiting through Earth's magnetic tail. Sensors on the spacecraft recorded jets of high energy particles emerging from the magnetotail – one jet aimed at Earth probably produced aurora.