The following is a Patent granted on a U.K. Patent Application filed on
February 21, 1958 by The English Electric Company Limited, Harold Aspden being
the sole inventor. It was published on March 28, 1962.
U.K. PATENT NO. 892,333
'HIGH TEMPERATURE ELECTRIC DISCHARGE APPARATUS'
Commentary: This patent application was filed by the author's employer
THE ENGLISH ELECTRIC COMPANY LIMITED. That was in in 1958 in the early days of
the research efforts directed at 'hot fusion' power generation.
patent specification opens with the usual preamble introducing the
We, THE ENGLISH ELECTRIC COMPANY LIMITED, of Queens House, 28
Kingsway, London, W.C.2., a British Company, do hereby declare this invention
to be described in the following statement:-This invention relates
to thermo-nuclear process control apparatus. It is the object of the invention
to provide a new and improved apparatus of the "ZETA" (Zero, Energy Thermal
Apparatus) type, in which a very high temperature is produced by a pinched
electrical discharge in a gaseous medium.
The invention provides a
thermo-nuclear process control apparatus comprising a discharge chamber and
transformer acting means for inducing an EMF to produce an electrical discharge
along a closed path within said chamber, the discharge constituting in effect a
secondary winding, and said transformer acting means including a primary winding
which has a configuration rendering it electrically equivalent to a hollow
conducting tube housing said chamber and the discharge path.
thermonuclear process control apparatus of the kind to which this invention
relates has been described on pages 160-164 of the January 31st, 1958, issue of
In this apparatus an electrical discharge is induced in
deuterium gas at low pressure by transformer action. The discharge constitutes,
in effect, a secondary winding of a transformer and has a high self-inductance.
By a pulsed energization of the primary winding a high current discharge having
a large inherent inductive energy is set up and as electromagnetic effects
promote a concentration of the discharge (by the so-called pinch effect} this
inductive energy is concentrated into a progressively smaller region surrounding
the discharge with the result that, although the current decays rapidly, the
energy when dissipated as heat is dissipated over a very concentrated region.
The effect of this is the production of very high local temperature in the
deuterium gas. Such high temperatures are necessary to promote fusion reactions
which liberate atomic energy.
A problem arises from the instability of
the discharge and it is known that one way of reducing such instability consists
in the provision of a magnetic field axially directed along the path of the
discharge. A further problem arises from the natural expansion tendency of a
current along a circular path, a feature which, in conjunction with the high
energy demands of the discharge, renders it desirable to use a pulsed discharge
which is regenerated intermittently.
An improved stability of the
discharge is desirable (a) because higher temperature may thereby be induced at
lower discharge currents and (b) because such stability is conducive to a more
compact design for a given power rating.
The invention provided for the
winding enclosing the toroidal discharge chamber to be segmented in a series
wound arrangement by which current supplied was forced to conform with a uniform
distribution and thereby assist in keeping the discharge central within the
Claim 5, which is an independent claim, reads:
Apparatus comprising a discharge chamber and transformer acting
means for inducing an EMF to produce an electrical discharge along a closed
path within said chamber, the discharge constituting in effect the secondary
circuit of the transformer acting means, and the primary circuit of the
transformer acting means comprising a two-terminal winding having a plurality
of conductor turns each substantially coextensive with said discharge path and
together distributed to have a configuration rendering the winding
electrically equivalent to a hollow conducting tube housing said chamber and
the discharge path and operative when current is passed between the two
terminals of the winding to determine the current distribution in the winding
independently of induced electromagnetic reaction effects of the discharge,
said turns being wound around the discharge path to progress angularly about
an axis defined by this path and establish, owing to this progression a
magnetic field in the direction of the discharge when the discharge is induced
by the energization of the two terminal winding.
Figure 6 of the
patent (presented below) shows a cross-sectional elevation view of an apparatus
embodying the invention but suitable for operation at a lower voltage than a
similar apparatus illustrated in Fig. 1 of the Patent.