Research published earlier today by a group of scientists from Israel with a prodigious history of extravagant and extraordinary hacks. The two techniques are named MAGNETO and ODINI and are the work of scientists at the Cyber Security Research Center at the Ben-Gurion University of the Negev in Israel. Both techniques function on the same premise of using malware installed on air-gapped devices inside the Faraday cage to regulate the workloads on CPU cores in order to control the magnetic fields emanating from the computer.
Source: https://www.bleepingcomputer.com/news/security/new-magneto-and-odini-techniques-steal-data-from-faraday-cage-protected-equipment/