From:
http://mtaonline.net/~hheffner/ZPE-CasimirThrust.pdf
ZPE-Casimir Inertial Drive
Horace Heffner July 2003
There has long been a search for a self contained infinite ISP
inertial space drive. Such a drive is possible if inertia is indeed
a zero point energy (ZPE), i.e. zero point field (ZPF) caused effect,
as proposed by authors like Hal Puthoff. I suggest that if the zero
point field can be excluded in part from a cavity, then inertia of
free-moving bodies in that cavity should be reduced. The Casimir
effect is produced by placing conductive surfaces close enough to
exclude some of the longer of wavelengths of the ZPF, which is
comprised of very short wavelengths. Plate separations greater than
atomic dimensions do produce measurable Casimir attraction between
conductive plates.
If the assumed principles are true, then an inertial drive can be
made by directing a jet in to a Casimir cavity that is bounded such
that the jet direction is fluidly reversed. A semicircular cavity
shape should work nicely, using an inert gas, like helium or argon,
as the propellant. Such cavities could be cut or etched into
sandwiched layers of ultrathin dielectrics separating structurally
strong metal layers. Alternately, they might be machined by electron
beams.
Fig 1. shows a cross section of a single "ZPE thrust cell". An array
of roughly semicircular groves of width roughly on the order of to
10^-6 meter are cut into a metallic surface. These are represented
in Fig. 1 as the "Thin Cavity". A matched array of thick groves is
cut into a strong low density faceplate that is placed over the array
of thin cavities such that a continuous gas path is formed from one
side of the plate to the other in each row cells, and the entire gas
flow (for a given row) is directed through the thin cavity of each
cell in that given row. The edge lateral walls of the thick
cavities, noted as the "Cross Cavity Flow Barrier" in Fig. 1, are
positioned so as to force the gas flow through the thin cavities.
The two plates make a 2 dimensional array of thrust cells fed by gas
at high pressure from the edges. The plates can be stacked to create
a 3 dimensional array of thrust cells. The plates need to be made as
light as possible, but the surface of the thin cell need to be
conductive in order to exclude ZPF radiation of some frequencies from
the cell.
The thrust cell widths might be on the order of 10^-5 m, and a layer
of cells on the order of 10^-4 m. This gives a cell density of about
10^5 x 10^5 x 10^4 cells/meter^3 = 10^14 cells/m^3. The cavity depth
might be about 10^-5 meter.
On each transition from thick cavity to thin cavity, the gas flow
transfers momentum to the walls due to the angular acceleration. The
gas "snakes" through the thrust cells. The momentum transferred in
the thin cavities is upward in Fig. 1. The momentum transferred in
the thick cavities is downward in Fig. 1. Since the same gas flows
through all cavities in a row, the mass flow for the cells is
identical. If there is no change of inertial mass in the thin
cavities, then no net thrust results. However, if the inertial mass
of the gas molecules/atoms is less in the thin cavities, then less
momentum is transferred toward the top of Fig. 1 by the gas when in
the thin cavities, and a net thrust develops downward in Fig. 1.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
--------------------------------------------------
|
|
| ------------------------------ ...
Repeated ->
| / \
| / Thin Cavity \
| / \
| / --> --> \
| | | |
| | --> v | Thrust
| | --> \ | |
------ ^ \ ------ |
/ ------------ v v
Gas --> / ^ | | -->
| | Cross- |
| Cavity |
Thick Cavity | Flow | Thick Cavity
| Barrier |
| | -->
Gas --> | | -->
| |
-------------------- ---------------------
|
|
Repeated -->
|
--------------------------------------------------
Entire Thrust Cell Layer Repeated
|
|
v Thrust cell layers can be
stacked into 3D arrays.
Fig. 1 - Cross Section Diagram of ZPE Thrust Cell Array
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
If we use r=10^-5 m, and v= 10^-4 m/s, we get a centrifugal force F =
m*(V^2)/r of about 10 N/kg. The gas flows through an orifice 10^-6m
x 10^-5 m, or 10^-11 m^2. Argon is 1.784 g/l. At 10^-4 m/s the flow
rate is 10^-14 g/s = 10^-17 kg/s. With an effective r of 10^-5 m,
the mass of gas accelerating is the volume 10^-11 m^2 x 10^-5 m =
10^-16 m^3 times the density, or (10^-16 m^3) (1.78x10^3 kg/(1000
cm^3)) (10^2 cm)^3/m^3 = 1.78x10^-10 kg. This gives a very rough
thrust per cell of about (10 N/kg)(1.78x10^-10 kg)/2 = about 10^-9 N
= 1x10^-10 kgf. Given 10^14 cells/m^3, we have (1x10^-10 kgf)(10^14
cells/m^3) = 10^4 kg of thrust per cubic meter of cells. However, if
the inertial mass reduction is only 0.01 percent, then the thrust is
only 1 kg per cubic meter of cells.
The principle problems and unknowns of the design at this point,
then, are (1) the amount of inertial mass reduction that can be
obtained, and (2) the flow velocity of gas that can be maintained
through the thin cavity slots.
Update 7/26/2009:
The above calculation has some errors, and it is for much too large
cells to produce much Casimir effect. The scale needs to be more on
the scale of 10-7 m to have an effect. Here is a re-do of the
calculation with approximate flow and pressure information:
Input pressure: 100 atm
Flow velocity: 0.0001 m/s
Equivalent pipe diameter: 1E-7 m
Path length: 1 m length
Density of argon at 100 atm: 0.167 kg/l = 167 kg/m^3
Viscosity of Argon: 0.02099 cP (centipoise)
Reynolds Number, R: 7.96 x 10^-5
Friction Factor, f: 8.04 x 10^5
Pressure at outlet: 495 psi
Pressure Drop: 974 psi
Volume Flowrate: 7.85 x 10^-16 l/s
Mass Flowrate: 1.31 x 10-16 kg/s
If we use r=10^-7 m, and v= 10^-4 m/s, we get a centrifugal force F =
m*(V^2)/r of about 0.1 N/kg. The gas flows through an orifice of
about 7.85x10^-15 m^2, at the flow rate of 10^-16 kg/s. With an
effective r of 10^-7 m, the mass of gas accelerating is the volume
(7.85x10^-15 m^2)*(0.5x10-7 m)/2 = 1.963x10^-22 m^3 times the
density, or (1.963x10^-22 m^3) (167 kg/m^3) = 3.28x10^-20 kg. This
gives a very rough thrust per cell of about (0.1 N/kg)(3.28x10^20 kg)
= 3.28x10^-21 N = 3.34x10^-22 kgf. The cell size is about 2x10^-7 m,
or about 5x10^6 per meter, or about 10^20 per m^3. Given 10^20 cells/
m^3, we have (3.34x10^-22 kgf/cell)(10^20 cells/m^3) = 0.0334 kgf or
33.4 grams of thrust per cubic meter of cells. However, if the
inertial mass reduction is only 0.01 percent, then the thrust is only
0.00334 grams of thrust per cubic meter of cells.
This design appears to be impractical. However, if a superfluid is
used the density and velocity can be greatly increased, while
simultaneously reducing the drive power requirements, except for
refrigeration.
With sufficiently advanced nano-technology, the drive cells could
each consist of a cavity with a thin disk that rotates half in the
cavity and half out. The half of the disk inside the cavity would
experience inertial mass reduction, and thus a reduction in
centrifugal force. The actual mass changes occur at the entry and
exits from the cavity, and thus have no instantaneous effect on the
vertical centrifugal forces at that time. Any energy required or
obtained entering the cavity due to Casimir forces is offset by the
effect of opposite forces upon exiting the cavity.
A device based on cavity inertial mass change should work many orders
of magnitude better using the spinning disk nano-technology approach,
or possibly a using a superfluid. Both can increase the density and
velocity by orders of magnitude, and thus the mass flow by orders of
magnitude and the centrifugal force by orders of magnitude cubed.
These options all have the drawback that vast numbers of complex nano-
structures need to be manufactured.
There is a superior method available for implementing the principle
of applying anisotropic centrifugal force to Casimir cavity
influenced inertial masses. This method consists of building up
alternate layers of material, thin layers of conducting or super-
conducting material, i.e. casimir cavity boundary layer material,
while sandwiching between them layers of readily compressible
material which is to be used as the inertial mass altering material.
The method further consists of accelerating this material in one
direction while compressed, and the other direction while not
compressed. Compressing reduces the size of the Casimir cavities,
thus increasing the effect and reducing the mass of the compressible
material sandwiched between the plates.
The compressible material is likely best implemented as a structure
of mixed property material, a vacuous (not dense) highly compressible
mesh matrix material enclosing layers or pieces of the material that
is to actually act as the inertial mass modifying material. For
cooling purposes the mesh material might best be permeable to a
cooling medium, or at least produce little heat from repeated
compression and expansion.
Call the fully constructed material, which consists of layers of
Casimir cavities, "thrust material". Having the material, it is then
only necessary to compress it while accelerating in one direction,
and release the compression when the material accelerates in the
other direction. For example, the thrust material can be mounted
around the edges of a wheel and compressed by piezo crystal action
only when to one direction from the wheel axis. This produces a net
force in the opposed direction. Diamond might make a good inertial
mass modifying material due to its close packed structure, high
electrical insulating properties, and excellent thermal conduction.
A fully solid state design is feasible. This design uses piezo
crystals in two axes. The thrust material is compressed in the x
axis for inertial mass reduction, and the much larger oscillated
motion is produced by piezo action in the y axis. The thrust is
developed in the y axis due to the reduced inertial mass on one half
of the y axis cycle, caused by compression of the thrust material in
the x axis direction during that half of the y axis cycle.
Update 8/9/2009:
Another design for a Casimir thruster, based yet again on the premise
that matter within a Casimir cavity has reduced inertia, is based on
oscillating a nano-structure beam into and out of a Casimir cavity.
A microelectromechanical system (MEMS) beam can be electronically
activated as a pendulum which oscillates in the MHz range. For
example, see US Patent 6,531,668. An array of beams are created in a
sheet array which can be placed over a plate with matching grooves
in it located so as to act as cavities for the beams when acting as
pendula. The beams then oscillate into and out of their repsective
cavities. When the beams are down in their respective Casimir
Cavities they all accelerate in a direction toward out of the cavity,
and when out of the cavity they accelerate in a direction toward
their cavities. This is an ideal arrangement for creating thrust in
the direction towards out of the cavities, because the beam ends will
have less mass when in the cavities.
For a very rough performance estimate, suppose silicon beams are used
that are 100 microns long, thickness 2 microns, and width 5 microns.
Assume only the far half of the pendulum is active in producing
force, giving an active volume 50 microns long, with thickness 2
microns, and width 5 microns. Using 2.33 g/cm^3 for silicon, we have
an active mass of 1.165x10^-12 kg. Assume it swings to a depth of 5
microns into the cavity, and at a rate of 4 MHz. Its total swing is
10 microns, so it covers that distance with an average velocity v of
(10 microns)*(2 * 4 MHz) = 80 m/s. It changes from v to -v twice
each 1/(4 MHz) = 2.5x10^-7 seconds, giving an average acceleration of
2*(80m/s)/(2.5x10^-7 s) = 6.4x10^8 m/s^2. Suppose the Casimir
cavity inertial mass change is 1/100th the gross mass. The effective
mass is then (1.165x10^-12 kg) * 0.1 = (1.165x10^-14 kg) . A net
force f = m*a = (1.165x10^-14 kg)*(6.4x10^8 m/s^2) = 7.46x10^-6 N =
7.6x10^-7 kgf is produced.
Assume the cavity plates are 30 microns thick and the beam support
plates are 30 microns thick, for a layer thickness of 60 microns or
16,600 layers per meter. Assume the beams are repeated every 10
microns laterally, or 100,000 per meter. Assume the beams are
repeated every 150 microns, or 6,600 per meter. The number of beams
per cubic meter is then 16,600 * 100,000 * 6,600 = 1.1x10^13. The
total force per cubic meter of pendula is then (1.1x10^13) *
(7.6x10^-7 kgf) = 8.3x10^6 kgf, or 8,300 metric tons. Now that is
robust! If the Casimir cavity induced mass change is only 1/100,000,
then the thrust per cubic meter of pendula is 8,300 kg. Still
robust! This is clearly the preferred method.
Even at the fairly large element sizes chosen for performance
estimating, this prospective performance is startling, though the
example scale is too large to be maximally effective. Using
nanotechnology the performance could be improved by orders of
magnitude. For example, Casimir cavities of width less than 1/10
micron, 100 nanometers, would be necessary to achieve significant
inertial mass reduction. This can be achieved by making smaller
beams, but also by extending into parallel slits of width less than
100 nm, rows of planar protrusions from the beam, protrusions which
are of less than 100 nm width extended from beams which are on the
order of a micron wide. When this is done only a percentage of the
pendulum mass is involved in actual inertial mass reduction, but,
given the cubic power distribution of the zero point field, the
effect should grow by at least the inverse square of the slit
widths. The limits to advancement of technology of this kind are
probably features on the order of 10-20 nm.
The density of silicon is 2.33 g/cm^3, or 2.33 metric tons per cubic
meter. A thrust of 8.3 metric tons per cubic meter then readily
permits building a craft capable of sustained acceleration above 1 g,
or 9.8 m/s^2. Even without doppler shifting of the zero point field,
this will result in exceeding light speed in c/g = 3x10^7 seconds,
or about 355 days, one year. However, the zero point field will
likely be blue shifted, thus increasing its energy density and thus
the thruster performance.
The main problem with this design is that, though Hal Puthoff and
others have theorized that inertial mass is reduced in a Casimir
cavity, no one knows for sure if so and how much. This general
design may provide a powerful test of Casimir cavity inertial mass
reduction, down to very small percentages of inertial mass reduction.
Best regards,
Horace Heffner
http://www.mtaonline.net/~hheffner/
