Elsevier Science Home
Computer Physics Communications Program Library
Full text online from Science Direct
Programs in Physics & Physical Chemistry
CPC Home

[Licence| Download | New Version Template] actl_v1_0.gz(99 Kbytes)
Manuscript Title: ASPECT: an advanced specified-profile evaluation code for tokamaks.
Authors: D.P. Stotler, W.T. Reiersen, G. Bateman
Program title: ASPECT
Catalogue identifier: ACTL_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 81(1994)261
Programming language: Fortran.
Computer: CRAY-2.
Operating system: UNICOS, SUN OS.
RAM: 152K words
Word size: 64
Peripherals: disc.
Keywords: Plasma physics, Magnetic confinement, Thermonuclear fusion, Tokamak reactor, Specified Profile transport.
Classification: 19.9.

Nature of problem:
The purpose of this code is to provide a quick, if largely empirical, assessment of the performance of a tokamak fusion reactor [1,2]. ASPECT first performs a steady-state analysis at a point in the density-temperature operating space determined according to a set of user-specified criteria. The code then carries out a time-dependent calculation which can be used to address, for example, auxiliary heating requirements and helium ash buildup.

Solution method:
For the steady-state portion of the calculation, the individual terms in the global power balance equation are estimated using user-specified radial plasma profiles. An expression for the energy confinement time is required; a number of popular forms are included in the code. The power balance equation is solved using a Brent algorithm subroutine [3]. The reactor performance is quantified using either the ignition margin parameter or the level of confinement required to achieve a specified ignition margin. For the time-dependent calculation, the temporal variation of the device parameters, the relative plasma density, and the relative auxiliary power must be input. A feedback procedure for limiting the total heating power in the plasma is available. Helium ash accumulation can be included with an adjustable global confinement time. The time-dependent global plasma evolution equations are integrated using Hindmarsh's LSODE algorithm [4]; this yields the plasma energy as a function of time. The integration can be iterated (via the Brent algorithm subroutine [3]) to determine the level of auxiliary input power required to reach a specific plasma energy at a certain time.

Restrictions:
Although ASPECT is designed for use with tokamak reactors, it should be applicable to any toroidal reactor device. It is limited, however, in that it considers only closed flux surfaces; this implies that the cross-section of devices with separatrices are modelled approximately. The behaviour of the scrape-off layer plasma is not considered either. A limit of some sort on the total heating power resulting from plasma-wall interactions would be desirable [5]. The code is also restricted in that it cannot treat time-varying profiles.

Unusual features:
The steady-state calculation provided by ASPECT is considerably more flexible than that provided by similar programs. The ability to solve for the required auxiliary power within the time-dependent calculation is also note-worthy.

Running time:
1 - 7 CRAY-2 CPU seconds.