English: Building on the success of the 2XIIB magnetic mirror device in the mid-1970s, the Lawrence Livermore Laboratory (now Lawrence Livermore National Laboratory) researchers developed plans for the $94-million Magnetic Fusion Test Facility (MFTF) as the next step toward a reactor. Before construction started in October 1977, physicists T. Kenneth Fowler and Grant Logan independently came up with an improvement: the idea of a “tandem mirror.” Two mirrors would be at the ends of a central cylinder where the plasma would be confined. The Laboratory moved quickly to build the Tandem Mirror Experiment (TMX), an $11.4 million fusion experiment to test the idea. Technician Sam Espinoza is shown checking the alignment of one of the mirror magnets as construction of the TMX construction neared completion. A magnetic mirror is a magnet thatcan be shaped like the seam of a baseball, which produces magnetic forces that increase in every direction away from the center of the mirror region. A fusion plasma shaped like a twisted bow tie is confined inside a magnetic mirror..