The psionic matrix (a.k.a. psi-matrix) emanated from Aiur.
The psionic matrix spread over the Koprulu sector.Protoss structures and, to a lesser extent, units, drew their energy from this matrix. While a nexus provided a link to this matrix, khaydarin crystal-based pylons were needed to actually tap into the energy required to provide psionic energy to new colonies. Each pylon generated a short-ranged aura of energy, which can provide the power needed by structures and warp gates. If a protoss building lost its connection to the psionic matrix, it would shut down until it was reconnected, and new units could not be gated in if there was insufficient psionic energy to provide them with power. The matrix could be "supercharged" by a mothership core, which allowed a nexus to use its energy as a defensive measure.
In 2506, the psionic matrix was dismantled to prevent Amon from recalling the Golden Armada to Aiur to defend his host body. The power structure in the Citadel of the Executor was destroyed by MatriarchVorazun and HighlordAlarak. The power structure on the temple grounds was destroyed by Phase-smithKarax and Fenix. Their actions released a massive overflow of psionic energy from the surface of Aiur. HierarchArtanis kept ahead of the energy storm and destroyed the power structure in the xel'naga caverns.
After the End War, the Daelaam reconstructed the psionic matrix, with a temple being build around its central hub. Funerals for fallen protoss were often done at this temple.