|Plasma beam weapon|
Directed energy weapon
Ship-to-ship energy weapon
- "...the Apollo and the Daedalus have been retrofitted with the new Asgard plasma beam weapon which—given—are very, very powerful..."
- —Rodney McKay
Plasma beam weapons are a newly developed technology created by the Asgard shortly before their extinction and gifted to the Tau'ri as part of their legacy. They appear far superior to the older Asgard weapons.
- "At least we now have weapons we know will destroy an Ori ship."
- —Cameron Mitchell
Instead of firing pulses of energy like most beam weapons, Asgard plasma beam weapons release a narrow, high-intensity beam of superheated plasma. Just one of these beams is capable of overloading and penetrating even the most advanced shields and burning through the hulls and internal structures of an enemy vessel with comparative ease, causing heavy damage; if the beam hits a critical area the target can be destroyed in only two to three shots. This incredible ship-to-ship weapon might be one of the most powerful and efficient ever encountered, easily comparable to the Ancient Drone weapons, although they work quite differently and require far less energy. (SG1: "Unending") (ATL: "Be All My Sins Remember'd")
While there are beam weapons that can discharge more raw power at once such as the Lagrangian Point satellite (which is almost the size of a Ha'tak vessel - certainly not a ship-based weapon) require an extended period of time and a significant amount of power to charge. In contrast, the advantage of the more advanced plasma beam weapons lies in their ability to come online and charge at an incredibly rapid rate (using up relatively little power in the process) and deliver several consecutive shots in only a few seconds, overwhelming enemy defenses while they are still recovering from the previous hits. Only one ship has ever been able to withstand this weapon; Goa'uld-shields can be overwhelmed by a single beam while the powerful shields on Ori warships starts to fluctuate greatly after 2 hits. After 3-4 hits the shield will fail and the ship itself will sustain crippling damage. Any further hits will make the warship explode. Not even the most advanced shields on the Asuran's version of Aurora-class battleships can withstand many hits from the Asgard plasma beams. It is unclear what sort of effect these beam weapons would have against Ancient warships. The Ancient-built Orion has different shielding systems than the Asurans version of the Aurora class. As such, it is possible that the Ancients may have upgraded their shielding systems and weapons as this ship was constructed later than the Asuran's version. However, it is not known whether even the upgrades would have had an effect on abating the advanced beam weapons, since the Asgard at the time of their extinction have proven to be on par or even surpass the Ancients in terms of technology. To date only a ZPM-enhanced Wraith Hive ship has been able to withstand plasma beams with minimal damage. (SG1: "Unending") (ATL: "The Siege, Part 1", "First Strike", "Be All My Sins Remember'd")
Asgard plasma beam weapons have been proven capable of easily destroying Ori warships (although Odyssey has one Zero Point Module) in 6 hits, Asuran Aurora-class battleships, in 9 hits (although one was destroyed in two hits, but it may have been damaged at the time), and Wraith Hive ships in three hits. The Super-hive, equipped with ZPMs, however, are virtually immune to these weapons, due to the far greater density of their hull. A direct hit will only result in minimal damage. (SG1: "Unending") (ATL: "Be All My Sins Remember'd", "The Last Man", "Search and Rescue", "Enemy at the Gate")
The weapon's power may be adjustable since it has been observed disabling a Wraith cruiser instead of destroying it. However, this may have also been managed instead by selective targeting. (ATL: "Search and Rescue")
- "I want to be able to brief the President as soon as we get back. He's gonna want to know how quickly we can duplicate this new Asgard weaponry."
- —Henry Landry
They saw action in the Battle of M2S-445, where they disabled Michael's cruiser's hyperdrive before destroying it as soon as Teyla Emmagan was rescued from the ship. They were later used in the Battle of the Super-hive, but were largely ineffective against the upgraded Hive due to its much-improved hull armor, with a direct hit resulting only in minimal damage. (ATL: "Search and Rescue", "Enemy at the Gate")
During the Battle of M35-117 in an alternate reality, an alternate Daedalus attacked an Alien ship with these weapons. While the few shots it was able to get off due to great lack of power weren't enough to destroy the alien ship, it disabled the ship's weapons and saved the alternate Atlantis. (ATL: "The Daedalus Variations")