Neutrinos are particles that pass through any matter easily, no matter how dense. The Omeyocans were able to create an environment where neutrinos were slowed down. (SG1: "Crystal Skull")
The Asgard utilized neutrino-ion generators, which put out 1 billion kilojoules of energy per second - one terawatt (for comparison, the total power usage of humans worldwide was 16 TW in 2006, and the average lightning strike peaks at 1 TW). (SG1: "Nemesis")