Understanding Debris-Background Ion Interactions in High Altitude Nuclear Explosions
The Starfish Prime event produced many interesting nuclear, electromagnetic, atomic and plasma effects, which have led over the past 50 years to much research in understanding the overall phenomenology of high altitude nuclear explosions (HANE). At altitudes lower than Starfish, where collisional processes come into play, the physics of a nuclear fireball in the atmosphere is well understood. But at high altitudes, where collisions are much weaker, the fundamental issue how the ionized weapon debris is stopped in the ionosphere in order to produce a relatively localized debris cloud remains unresolved. In the last 30 years this issue has been investigated in the laboratory using high-power lasers to simulation the explosion and subsequent expansion of the debris plasma. While experiments that were carried out on the Helios laser at Los Alamos and then later on the Pharos laser at NRL were able to produce some plasma conditions representative of the HANE environment and obtained interesting results, they were not very successful in addressing the basic debris-air coupling problem in the collisionless regime. This problem is being revisited in a new DTRA-funded experimental program with the 500 J Raptor glass laser on the Large Plasma Device (LAPD) at UCLA.