7 Numerical Simulation of Generation, Distribution, and Impact …
89
model the initial and subsequent stage of TPB motion in a rarefied gas and the
impact of a high-velocity flow on the surface of a solid body.
The chapter is organized as follows. Section 7.2 describes the general principles of
plasma gun functioning and the physical picture of plasma clot formation. Section 7.3
provides a physical and mathematical statement of the initial stage of the problem to
be solved. Due to the fact that this problem is quite complex both mathematically and
especially physically, it made sense to solve the problem sequentially numerically
with gradual connection of physical processes. Section 7.4 presents the results of
the calculation in the adiabatic approximation (without taking into consideration
internal kinetic processes and Joule heating). And in Sect. 7.5, calculations of the
initial stage of CT dynamics are given in full statement. Based on studies of the initial
stage of formation and movement of CT, calculations of its further movement in the
ionosphere were made and its influence on the ionosphere was estimated. Section 7.6
is dedicated to this. Section 7.7 shows the effect of a rarefied plasma flow of certain
duration on a crystal and amorphous structure of the glass type. Section 7.8 concludes
the chapter.
7.2 Physical Picture of the Formation and TPB Dynamics
Electromagnetic shock tubes used for the creation of intense shock waves have been
known for a rather long time. Their operation is based on the effects of gas heating
by an electric discharge and its acceleration under the action of magnetic forces. The
discharge current flows in the radial direction between electrodes, one of which is
a rod positioned on the tube axis and the other is a cylinder near the tube surface.
The radial current of the discharge interacts with the concentric magnetic field of the
current itself and the current flowing along the central electrode. The ponderomotive
force is directed along the tube axis and accelerates the plasma in this direction.
The further development of works in this area was related to the creation of plasma
guns. An important distinctive feature of plasma guns is the presence of a powerful
toroidal current in the torus-shaped plasma bunch ejected from the generator. As
shown by [1], the radial magnetic field forming the toroidal current is created by a
special current coil placed in the initial part of the channel. During CT motion in this
field, the toroidal current creates its own poloidal magnetic field, which exercises a
decisive influence on the preservation of the compact structure of the plasma bunch
at the initial stage of its motion after the escape from the generator.
The geometry of the plasma bunch upon exit from the pulsed plasma accelerator
has approximately the following characteristics, as shown in Fig. 7.1.
We assume that the toroidal current in TPB is determined by the radial component
of the magnetic field B r . The component is created by a coil with a current of I k ∼ = 5
kA and a distance of δ ∼ = 1−3 cm from the coil to TPB surface. The radial component
of the magnetic field in the region inside TPB can then be estimated as
89
model the initial and subsequent stage of TPB motion in a rarefied gas and the
impact of a high-velocity flow on the surface of a solid body.
The chapter is organized as follows. Section 7.2 describes the general principles of
plasma gun functioning and the physical picture of plasma clot formation. Section 7.3
provides a physical and mathematical statement of the initial stage of the problem to
be solved. Due to the fact that this problem is quite complex both mathematically and
especially physically, it made sense to solve the problem sequentially numerically
with gradual connection of physical processes. Section 7.4 presents the results of
the calculation in the adiabatic approximation (without taking into consideration
internal kinetic processes and Joule heating). And in Sect. 7.5, calculations of the
initial stage of CT dynamics are given in full statement. Based on studies of the initial
stage of formation and movement of CT, calculations of its further movement in the
ionosphere were made and its influence on the ionosphere was estimated. Section 7.6
is dedicated to this. Section 7.7 shows the effect of a rarefied plasma flow of certain
duration on a crystal and amorphous structure of the glass type. Section 7.8 concludes
the chapter.
7.2 Physical Picture of the Formation and TPB Dynamics
Electromagnetic shock tubes used for the creation of intense shock waves have been
known for a rather long time. Their operation is based on the effects of gas heating
by an electric discharge and its acceleration under the action of magnetic forces. The
discharge current flows in the radial direction between electrodes, one of which is
a rod positioned on the tube axis and the other is a cylinder near the tube surface.
The radial current of the discharge interacts with the concentric magnetic field of the
current itself and the current flowing along the central electrode. The ponderomotive
force is directed along the tube axis and accelerates the plasma in this direction.
The further development of works in this area was related to the creation of plasma
guns. An important distinctive feature of plasma guns is the presence of a powerful
toroidal current in the torus-shaped plasma bunch ejected from the generator. As
shown by [1], the radial magnetic field forming the toroidal current is created by a
special current coil placed in the initial part of the channel. During CT motion in this
field, the toroidal current creates its own poloidal magnetic field, which exercises a
decisive influence on the preservation of the compact structure of the plasma bunch
at the initial stage of its motion after the escape from the generator.
The geometry of the plasma bunch upon exit from the pulsed plasma accelerator
has approximately the following characteristics, as shown in Fig. 7.1.
We assume that the toroidal current in TPB is determined by the radial component
of the magnetic field B r . The component is created by a coil with a current of I k ∼ = 5
kA and a distance of δ ∼ = 1−3 cm from the coil to TPB surface. The radial component
of the magnetic field in the region inside TPB can then be estimated as