ISSN 0021-8944, Journal of Applied Mechanics and Technical Physics, 2018, Vol. 59, No. 1, pp. 9–13.
Pleiades Publishing, Ltd., 2018.
Original Russian Text
D.Yu. Gerasimov, A.A. Sivkov.
INCREASE IN THE ACCELERATION EFFICIENCY OF SOLIDS
IN A HYBRID COAXIAL MAGNETOPLASMA ACCELERATOR
D. Yu. Gerasimov and A. A. Sivkov
Abstract: It is shown that in a hybrid coaxial magnetoplasma accelerator with a channel length
of 350 mm and a diameter of 23 mm, the acceleration velocity and the energy conversion eﬃciency
increase as the length of the plasma structure formation channel ﬁlled with a gas-generating material
decreases from 17 to 9 mm. It is found that it is reasonable to use paraﬃn as the gas-generating
material as it has a less signiﬁcant deionizing eﬀect on the high-current arc discharge and hence
causes a less signiﬁcant decrease in the discharge current intensity and an increase in conductive and
inductive electrodynamic forces.
Keywords: hybrid coaxial magnetoplasma accelerator, acceleration of solids, plasma structure
formation channel, gas-generating material.
The characteristics of a hybrid coaxial magnetoplasma accelerator (HCMPA) designed to convert electromag-
netic energy into the kinetic energy of projectiles weighing up to 100 g at a power source current of up to 250 kA .
Energy conversion in the HCMPA is carried out using simultaneously electro-explosive and electrothermal processes,
as well as the principles of conductive and inductive electrodynamics. The electrothermal mechanism is based on the
thermal decomposition of a hydrogen-saturated gas-generating material (GGM) under high-current arc discharge.
In the accelerator considered , GGM was located in the plasma structure formation channel (PSFC). It was
established that GGM can be readily available materials such as paraﬃn, petrolatum, and transformer oil (using
an absorbent material) which are safe under normal conditions . These materials comprise hydrogen, which
is released during thermal decomposition, heated by the discharge plasma, and performs work mainly during the
initial period of projectile acceleration. The product hydrogen concentration is 1.65 g/liter for the decomposition of
paraﬃn, 1.59 g/liter for the decomposition of petrolatum, and 1.47 g/liter for the decomposition of transformer oil.
Thus, the study of the inﬂuence of the type of GGM and the geometry of the PSFC accelerator on the eﬃciency of
energy conversion in the HCMPA is an urgent task.
The apparatus and principle of operation of the accelerator are described in . The experiments were
carried out under the following conditions. The capacitance of the capacitor bank of the energy storage system was
C =38.4 mF, the charge voltage U
=3.5 kV, and the storage energy W
= 235 kJ. Barrels of length l
= 350 mm
and diameter d
= 23 mm were made of stainless steel (Fig. 1), the central electrode of the accelerator was made
of St. 3 steel, and the insulator of ﬁberglass. The PSFC had the shape of a cylinder, and the mass of the GGM
was 1.3 g. Petroleum and paraﬃn were used as GGM. Projectiles were made of steel and the obturators of copper
(see Fig. 1). The gas pressure was maintained using a bottom obturator made of high-density polyethylene. In
the experiments, projectiles of mass (54.3 ± 1.4) g were used. To study the inﬂuence of the PSFC geometry, we
carried out shots at a channel length equal to 17, 12, and 9 mm and its constant volume and hence constant mass
Tomsk Polytechnic University, Tomsk, 634050 Russia; firstname.lastname@example.org; SivkovAA@mail.ru. Translated
from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 59, No. 1, pp. 13–18, January–February, 2018. Original
article submitted February 26, 2016; revision submitted November 24, 2016.
2018 by Pleiades Publishing, Ltd.