The Warp Propulsion Design Bureau has for decades attempted to design a compact, yet powerful warp core. The standard Vertical Intermix Assembly (VIA) maintenance records show a higher than expected rate of preventive, routine maintenance, and injector unit replacement. Designers knew that increasing the number of injectors and firing them in rotation would extend the units' life expectancy. The problems faced miniaturizing the magnatomic force fields (used to contain the plasma) were overwhelming. During to the Dominion War, examination of a captured Jem'Hadar vessel gave clues to a breakthrough in this miniaturization.

The Toroidal Matter Antimater Reactor (T/MARA) core is an assembly of many seperate warp core reactors linked together annularly, whose individual plasma streams are converged in the center and directed to the warp propulsion system, and the electro-plasma power system. Although the test model worked fine, many engineers disliked it because it did not afford them an visual clues to its operation, unlike the VIAs.

Designers went back to the drawing board and developed a more tell-tale core. The new model was based upon older, standard MARAs. This actually made things easier for the engineers because it was more familiar and readily adaptable to known operational protocols.

The main goals behind the T/MARA is reduncancy, extended lifetime of key components, and greater power output. The T/MARA is consructed of segments that have a number of injector systems inside. The smallest standard T/MARA is a 3:6 arrangement. This means that there are three injectors to each segment that number six. This gives a total of 18 small vertical MARAs. The Rapier class has two 3:6 T/MARAs, one for each engine. The warp core is not designed to fire all injectors simultaneuosly for long durations. Normal power output can be achieved at a 50% firing rate. Each injector in a segment fires one at a time under nominal conditions. For greater power needs the number of injectors firing in each segment, and their rate of fire, can be increased. The power output depends on the type of T/MARA in use.

Other configurations are: 4:8, 5:10, 6:12. Larger vessels with more power allocations use larger configurations. Tests had showed that smaller T/MARAs could handle such loads, but suffered more operational stresses leading to more frequent repair and calibration needs, thus failing the main goals. It's compactness can give shuttles, runabouts, and fighters unpreceedented power.

Refitting vessels with VIA to TIAs has been deemed impractical. The design of the T/MARA is incompatible with the warp plasma and EPS systems of existing vessels. The main problem lies with the different core and ejection system configurations. It is unlikely that aGalaxy or Sovereign class ship will be fitted with the T/MARA, unless new ships are built keel-up to accept the core. An extensive redesign of the engineering section would be required in any case. Refitting smaller ships, such as the Akira, Defiant or Sabre classes is being looked into.