Historical research guide · 0025 · 2011
Warp Field Mechanics 101
White, Harold
In one minute
Harold ‘Sonny’ White’s NASA Johnson report examines Alcubierre’s 1994 metric: a bubble of flat local space that contracts distance ahead of a craft and expands it behind. The craft does not move faster than light through its own local surroundings. White rewrites the metric in canonical form and uses its boost factor to describe the motion. His analysis finds that, for a fixed radius and target velocity, a thicker bubble wall reduces the peak and total energy requirement. It also specifies a laboratory measurement: a 633 nm helium-neon laser interferometer could resolve a boost of 1.0000001 across one centimetre from a toroidal test article. The report gives a metric, an energy relation and an interferometric test, rather than a reported warp-field measurement.
Connection
This is the paper chapter 4 is built on: metric engineering with an equation, a test article and a number to beat, from a NASA laboratory. The field it calls for carries a negative energy density, which is what ties chapter 4 straight back to the vacuum chapters 2 and 6.
From the source
Because the expansion and contraction of space has no speed limit, the Alcubierre metric lets a craft cross any given cosmic distance in an arbitrarily short time while never locally breaking the speed of light; the proper acceleration inside the bubble is zero and shipboard clocks beat at the same rate as clocks on Earth.Alcubierre metric, equations 1–3 (Alcubierre, Class. Quant. Grav. 11, L73, 1994)
A finding new to the literature: for a fixed target velocity and bubble radius, allowing the warp bubble wall to get thicker drastically reduces the peak energy density the field requires, and the analysis behind Figures 1 and 2 shows a corresponding reduction in total energy — sloppy warp fields would appear to be easier to engineer than precise warp fields.Alcubierre metric, discussion of Figure 2; Conclusion
Written in canonical form, the metric gives a field potential φ and a boost γ = cosh(φ); taking the boost rather than the York Time as the driving phenomenon resolves the asymmetry/symmetry paradox, since the boost multiplies an initial sub-luminal velocity — a craft at 0.1c with a boost of 100 reaches Alpha Centauri in 0.43 years by both Earth and shipboard clocks.Alcubierre metric, equation 4 and the modified concept of operations
Comparing the null-like geodesics of the Alcubierre metric with the Chung-Freese higher-dimensional metric shows that the hyperspace coordinate serves the same role as the boost, informally γ ~ e^U: a large boost corresponds to an object sitting further off the brane and into the bulk.Chung-Freese metric, equation 5 and the null-like geodesic equation
A warp subsystem generating a negative energy density adds negative mass to the vehicle’s mass budget: on a 5,000 kg, 100 kW solar-electric tug, about 2,000 kg of negative mass drops the specific mass from 50 to 30 kg/kW and cuts the Earth-to-L1 transit from about 70 days to about 40, with transit time approaching zero as the negative mass approaches the vehicle’s own mass.Mission planning with a warp-enabled system; Figure 4
A warp field interferometer at the Advanced Propulsion Physics Laboratory: Eagleworks, using a 633 nm helium-neon laser, should resolve space perturbations of about one part in 10,000,000 across 1 cm, so a 1 cm toroidal test article — something as simple as a very high-voltage capacitor ring — producing a boost of order 1.0000001 would be detectable.Advanced Propulsion Physics Lab: Eagleworks; Figure 5
The way in
https://ntrs.nasa.gov/citations/20110015936How to cite it
White, Harold (2011) Warp Field Mechanics 101 https://ntrs.nasa.gov/citations/20110015936