Speaker
Anton Vyacheslavovich Sudnikov
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P2.1054.pdf
First Experiments on Helical Mirror Device SMOLA
A.V. Sudnikov1,2, A.D. Beklemishev1,2, A.V. Burdakov1,3, I.A. Ivanov1,2,
A.A. Inzhevatkina2, V.V. Postupaev1,2
1
Budker Institute of Nuclear Physics, Novosibirsk, Russia
2
Novosibirsk State University, Novosibirsk, Russia
3
Novosibirsk State Technical University, Novosibirsk, Russia
Plasma confinement in modern open magnetic traps features high relative pressure (β ≈ 60%),
mean energy of hot ions of 12 keV and electron temperature ~ 1 keV [1]. At the same time,
the confinement efficiency is limited by the achievable magnetic field; the mirror ratio is
supposed to be 15–20 in neutron source concepts [2]. Higher fusion gain in linear plasma
devices is possible with improved confinement. The existing technique of multiple-mirror
suppression of the axial heat flux combined with gas-dynamic central cell [3] can provide
effective mirror ratios >100, which gives feasible fusion gain appropriate for hybrid systems.
This report presents the first experimental results on the new method of active plasma flow
suppression in a helical magnetic field [4]. This method renews the idea of a plasma flow
control with moving mirrors. Plasma rotation in E×B fields can be utilized to create periodical
variations of helicoidal magnetic field moving upstream in plasma’s frame of reference. These
variations transfer momentum to trapped particles and lead to plasma pumping towards the
central trap. Theory predicts exponential dependence of the flow suppression on the magnetic
structure length, that is more favorable then the power dependence in passive mirrors [5].
Plasma biasing or natural ambipolar potential can drive the rotation. The first case also leads
to plasma pinching that counteracts the collisional radial diffusion.
Concept exploration device SMOLA with a helical mirror system [6] started operation in a
start configuration in BINP in the end of 2017. Major aims of the first experiments were
preliminary observations of plasma behaviour at changes of the magnetic configuration,
regardless of the confinement efficiency. Plasma stream modification with the helical
plugging was clearly shown. In this report, the main results of the experiments are discussed.
[1] P. A Bagryansky, et al., Phys. Rev. Lett. 114, 205001 (2015).
[2] A. V. Anikeev, et al., Materials. 8, (No. 12), 8452 (2015), DOI: 10.3390/ma8125471.
[3] V.V. Postupaev, et al., Nuclear Fusion, 57, 036012 (2017).
[4] A. D. Beklemishev, Fusion Sci. Technol. 63 (No. 1T), 355 (2013).
[5] A. D. Beklemishev, AIP Conference Proceedings. 1771, 040006 (2016).
[6] A. V. Sudnikov, Fusion Engineering and Design. 122, 85 (2017), DOI: 10.1016/j.fusengdes.2017.09.005],
