For 10 points, name this speculative technology which was used to destroy the planet of Alderaan by the Death Star.
Harry Grindell Matthews was offered $25,000 to demonstrate one of these devices at Madison Square Garden but failed to collect the prize because, despite his boasting, he didn't actually invent one.  During World War II, the Japanese supposedly developed a weapon of this type called a Ku-Go, and Mussolini tasked Marconi with inventing one.  President Obama personally challenged the (*) Mythbusters to test a myth involving one of these devices.  Actual types of these devices include Raytheon's Silent Guardian, euphemistically called an Active Denial System.  In his 70s, Nikola Tesla set out to create the Teleforce, one of these devices.   One built from mirrors was allegedly constructed during a siege of Syracuse by Archimedes.  For 10 points, name this speculative technology which was used to destroy the planet of Alderaan by the Death Star.
Harry Grindell Matthews was offered $25,000 to demonstrate one of these devices at Madison Square Garden but failed to collect the prize because, despite his boasting, he didn't actually invent one.  
death ray [or solar ray or death beam or heat rays or directed energy weapons] Â 