Operation of Inertial Electrostatic Confinement Fusion (IECF) Device
Using Different Gases
Gamal M. Elaragi
Published online: 19 January 2018
Ó The Author(s) 2018. This article is an open access publication
An optical signal of IEC plasma using different gases has been registered by means of an optical ﬁber and photomultiplier
(PMT). The light passing through the ﬁber is directed to the entrance window of a photomultiplier (PMT, Hamamatsu
R955), connected to the digital scope. The discharge current of plasma discharge has been recorded using current probe.
The X-ray emission in IEC plasma device was investigated by employing time-resolved detector.
Keywords IEC Á Discharge current Á Plasma discharge Á X-ray
Inertial electrostatic conﬁnement (IEC) is considered to be
a promising future technology for space applications
especially for advanced space propulsion systems. Since
this technology was mainly investigated and developed for
applications as neutron source until a few years ago, a great
potential and need for investigations regarding discharge
phenomena such as the propellant conﬁnement and the jet
extraction for thrust generation is still existent.
Unfortunately this principle suffers from many inherent
loss mechanisms, which lead to a quick loss of ions at a
small timescale and prevent a sufﬁcient fusion gain [1, 2].
Over the two last decades IEC devices have been mainly
developed in two directions: The ﬁrst one is the use as
economical neutron sources with applications such as
medical isotope production [3, 4] or baggage screening .
Other approaches have been taken into the direction of the
development of a non-fusion plasma jet source for space
propulsion [6, 7]. However, IEC devices have as well been
proposed as a fusion energy source for future spaceships
[2, 8, 9]. Most of these devices use a setup with a smaller
grid nested inside a larger grid. These are usually spherical
wire grids that feature a high transparency, but the
openings between the wires have an unregularly shape and
position. The average lifetime of ions in the plasma should
be as long as possible .
One of the principal considerations while building a grid
is to improve the grid transparency. Operation in the star
mode depends more on the effective transparency versus
the geometric transparency. However, operation in other
modes is very dependent on the geometric value, so
improvements in the geometric transparency are very
desirable . The material of grids for high power IEC
devices has to withstand temperatures of up to 2000 K
because ion bombardment can lead to rapid heating and
material sputtering. For low power test devices, stainless
steel provides an easier alternative for manufacturing.
Novel approach for improving the neutralization in ion-
injected IEC devices involves the active injection and
conﬁnement of electrons to the center of the device, to
create dense, neutralizing plasma in the core region.
Enhanced neutralization allows for higher ion densities and
populations, and consequently higher fusion rates .
The IEC consists of a cylindrical vacuum chamber made of
Pyrex glass tube with 10 cm of diameter and 30 cm height.
The inner electrode consist of two stainless steel rings
which are welded in their joint places (Fig. 1) and spiral
outer electrode made of stainless steel. Figure 1 displays
& Gamal M. Elaragi
Plasma Physics and Nuclear Fusion Department, Nuclear
Research Center, EAEA, Cairo, Egypt
Journal of Fusion Energy (2018) 37:37–44