Alpha – particle confinement control and Alfven wave-particle interaction
Two important physics effects are found in the interaction of the particle with the electromagnetic field of Alfven type wave in the toroidal magnetic trap: the increase/decrease of the radial deviation of the particle under the effect of the switching on/off of the time dependent part of the electr...
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2000
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| Цитувати: | Alpha – particle confinement control and Alfven wave-particle interaction / A.A. Shishkin and O.A. Shishkin // Вопросы атомной науки и техники. — 2000. — № 3. — С. 16-18. — Бібліогр.: 8 назв. — англ. |
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irk-123456789-823602015-05-29T03:02:06Z Alpha – particle confinement control and Alfven wave-particle interaction Shishkin, A.A. Shishkin, O.A. Magnetic Confinement Two important physics effects are found in the interaction of the particle with the electromagnetic field of Alfven type wave in the toroidal magnetic trap: the increase/decrease of the radial deviation of the particle under the effect of the switching on/off of the time dependent part of the electromagnetic perturbation. 2000 Article Alpha – particle confinement control and Alfven wave-particle interaction / A.A. Shishkin and O.A. Shishkin // Вопросы атомной науки и техники. — 2000. — № 3. — С. 16-18. — Бібліогр.: 8 назв. — англ. 1562-6016 http://dspace.nbuv.gov.ua/handle/123456789/82360 533.9 en Вопросы атомной науки и техники Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
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Magnetic Confinement Magnetic Confinement |
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Magnetic Confinement Magnetic Confinement Shishkin, A.A. Shishkin, O.A. Alpha – particle confinement control and Alfven wave-particle interaction Вопросы атомной науки и техники |
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Two important physics effects are found in the interaction of the particle with the electromagnetic field of Alfven type wave in the toroidal magnetic trap: the increase/decrease of the radial deviation of the particle under the effect of the switching on/off of the time dependent part of the electromagnetic perturbation. |
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Article |
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Shishkin, A.A. Shishkin, O.A. |
| author_facet |
Shishkin, A.A. Shishkin, O.A. |
| author_sort |
Shishkin, A.A. |
| title |
Alpha – particle confinement control and Alfven wave-particle interaction |
| title_short |
Alpha – particle confinement control and Alfven wave-particle interaction |
| title_full |
Alpha – particle confinement control and Alfven wave-particle interaction |
| title_fullStr |
Alpha – particle confinement control and Alfven wave-particle interaction |
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Alpha – particle confinement control and Alfven wave-particle interaction |
| title_sort |
alpha – particle confinement control and alfven wave-particle interaction |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
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2000 |
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Magnetic Confinement |
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http://dspace.nbuv.gov.ua/handle/123456789/82360 |
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Alpha – particle confinement control and Alfven wave-particle interaction / A.A. Shishkin and O.A. Shishkin // Вопросы атомной науки и техники. — 2000. — № 3. — С. 16-18. — Бібліогр.: 8 назв. — англ. |
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Вопросы атомной науки и техники |
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| fulltext |
Problems of Atomic Science and Technology. 2000. N 3. Series: Plasma Physics (5). p. 16-18
16
UDC 533.9
ALPHA – PARTICLE CONFINEMENT CONTROL AND ALFVEN WAVE-
PARTICLE INTERACTION
Alexander A.Shishkin and Oleg A.Shishkin*
Institute of Plasma Physics, National Science Center, “Kharkov Institute of Physics and
Technology”, Academicheskaya str. 1, Kharkov –108, 61108, UKRAINE
and
Plasma Physics Chair, Department of Physics and Technology,
Kharkov “V.N. Karazin” National University, Kharkov-77, 61077, UKRAINE
* Plasma Physics Chair, Department of Physics and Technology,
Kharkov “V.N. Karazin” National University, Kharkov-77, 61077, UKRAINE
Two important physics effects are found in the interaction of the particle with the electromagnetic field of Alfven
type wave in the toroidal magnetic trap: the increase/decrease of the radial deviation of the particle under the effect
of the switching on/off of the time dependent part of the electromagnetic perturbation.
1. Introduction
Confinement of the “hot” alpha–particles, removal
of the “cold” alpha-particles and screening the bulk
plasma from the impurity ions with the high charge
number Z released from the wall, divertor and target
materials are the subject of the study of the modern
fusion reactor physics. Different methods are known to
enhance the confinement of the “hot” alpha–particles,
this is the optimization of the magnetic configuration,
especially (see, for instance [1]). For the removal of
“cold” alpha-particles there are proposed different
approaches which are connected with the externally
applied magnetic field perturbations, the use of isolated
drift resonances (drift islands) and overlapping of
adjacent resonance (stochasticity) [2-5]. For the
screening plasma from the penetration of impurity ions
different types of divertors are developed and
optimized. The control of particle motion with the use
of electromagnetic waves is also possible [6,7].
In this paper we consider the methods, which use the
“wave – particle” interaction to control the test particles
of different energy range. The selectivity of this effect
concerning the energy W and mass M of particles is
realized.
2. Transit Orbit under the Helical Field Change
As it is known [4] the passing particles, which
satisfy the resonance condition with, the externally
applied perturbation magnetic field (namely nm /* =ι )
can be transported across the magnetic surfaces with the
use of such physics effect -“drift island motion”. This
mechanism is rather effective to remove the “cold”
alpha-particles from the plasma core of the reactor.
However it is demonstrated [4] that this mechanism is
possible for the passing particles. The trapped particles
should escape due to the drift motion in the
inhomogeneous magnetic field. Transit particles (which
transform the state from the helically trapped into the
blocked and back) should be the subject of study.
Here we consider the effect of the slowly changed
helical magnetic field on the “cold” alpha-particles
( 350=W keV) with the transit orbits. There is taken the
magnetic configuration with 3=l torsatron-type helical
winding with the drift-optimized properties [1].
In the case when the amplitude of the helical field
does not change in time the transit particle does not
come out from the confinement volume (Fig.1).
1750 2000 2250
R (cm)
-250
0
250
Z
(
cm
)
Fig.1. The trajectory of the transit “cold” alpha-
particle in the vertical plane of reactor scale
configuration
The transit character of the trajectory one can see
from the dependence of the velocity pitch VV /||
on the
time t (Fig.2.).
0 4000 8000 12000 16000
-0.8
-0.4
0.0
0.4
0.8
Fig.2.The dependence of VV /||
on the time t
Problems of Atomic Science and Technology. 2000. N 3. Series: Plasma Physics (5). p. 16-18
17
The radial variable “oscillates” but the maximum
value does not increase in time (Fig.3).
0 5000 10000 15000 20000 25000
160
180
200
220
240
r
(c
m
)
Fig.3.The radial variable of the transit particle versus
the time
When the amplitude of the helical field changes in
time (Fig.4) the properties of the transit particle change
considerably (Fig. 5-7).
0 10000 20000 30000 40000 50000
0.36
0.40
0.44
0.48
Fig.4.The change of the amplitude of the helical field in
time
1750 2000 2250
R (cm)
-250
0
250
Z
(
cm
)
Fig.5.The trajectory of the transit particle under the
change of the helical field amplitude
This is not the full trajectory but the part of the
trajectory, which shows that particle becomes the
helically trapped one.
0 5000 10000 15000 20000 25000
-0.8
-0.4
0.0
0.4
0.8
Fig.6. The dependence of VV /||
on the time t of the
transit particle under the change of the helical field
amplitude
0 10000 20000 30000 40000 50000
160
180
200
220
240
260
r
(c
m
)
Fig.7. The radial variable of the transit particle versus
the time under the change of the helical field amplitude
This figure demonstrates the effect: the particle
becomes helically trapped and escapes from the
confinement volume.
3. Particle –Wave Resonance Conditions
The interaction of the Alfven-type magnetic
perturbation with the “cold”-alpha particle is
considered. The magnetic field perturbation is taken in
the form [8]
BrotB αδ = ,
where )sin( pnm tnm δωϕθαα ++−= . Here nm, are the
wave numbers, ω and
pδ are the frequency and the
phase of the wave. Here is shown the process of the
disruption of the resonance in the case when the
frequency ω is “switched off” (Figs.8-10). The
resonance 3/1* =ι is considered and the frequency
value is taken
||mV=ω .
Problems of Atomic Science and Technology. 2000. N 3. Series: Plasma Physics (5). p. 16-18
18
Fig.8. The electromagnetic field frequency switching on
/off
Now it is possible to discuss some consequences of
the combined effect of the magnetic resonance field and
the electromagnetic field (the time dependent term).
One can see the reduction of the radial deviation of the
test particle after the switching off of the
electromagnetic field (frequency switching off)
(Fig.10).
1750 2000 2250
R (cm)
-250
0
250
Z
(
cm
)
Fig.9. Disruption of the island structure during the
motion of the particle after the electromagnetic field
switching off
0 10000 20000 30000
120
160
200
240
280
r
(c
m
)
Fig.10. The radial variable versus time in the process of
the disruption of the resonance
The radial variable increases if the electromagnetic
field frequency is switched on (Fig.11). It means that
this test particle can escape and be removed from the
confinement volume.
0 5000 10000 15000 20000 25000
120
160
200
240
280
320
r
(c
m
)
Fig.11. The radial variable versus the time in the case
when the frequency is” switched on”
4. Conclusions
4.1. “Cold” alpha-particles with the transit orbits
(transforming from the helically trapped ones into
blocked ones and back) can be removed from the
plasma core in the case of slowly changed helical field
amplitude.
4.2. There exist the possibility to obtain the control
of particle with the combined effect of the magnetic
perturbations and electromagnetic wave launched by the
external antenna when the switching on /off of the
electromagnetic field is programmed in time.
References
[1] Shishkin, O. A. Reduction in deflections of α -
particle orbits in a thermonuclear reactor with an l=3
helical winding. Tech.Phys.Lett. 23 (1997) 895.
[2] Mynick, H.E. Stochastic transport of MeV ions by
low-n magnetic perturbations. Phys.Fluids B 5 (1992)
1439.
[3] Shishkin, A.A. Estafette of Drift Resonance,
Stochasticity and Control of Particle Motion in a
Toroidal Magnetic Trap, (this Conference).
[4] Motojima, O. and Shishkin, A.A. Drift island
motion in helical plasma and its use fro ash removal
and high-energy ion injection. Plasma Physics and
Controlled Fusion 41(1999) 227.
[5] Shishkin, A.A., Motojima, O. Polunovskiy, E. I.
Broadening of the particle resonance drift trajectory
and tritium injection into a fusion reactor with an a l=3
helical winding. Tech. Phys. Lett. 25 (1999) 43.
[6] Samoilenko, Yu.I. Problems of Micro-processes
Control in Continuous Substances. 10th All Union
Meeting on Control Problems, Sept.27 – Oct.03, 1986.
Talk Abstracts, Moscow 1986, part1, pp. 92-93 (in
Russian).
[7] Loginov, A.A. Selective Control of Processes in
Continuous Substances. Regulation of Objects with the
Spread Parameters, Proc. of Science Papers,
“V.M.Glushkov” Institute of Cybernetics of Academy
of Science Ukr.SSR, 1987, pp.31-36 (in
Russian).
[8] White, R.B. and Chance, M.S. Hamiltonian guiding
center drift orbit calculations for p lasmas of arbitrary
cross section. Phys. Fluids 27 (1984) 2455.
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