Measurements of runaway electron synchrotron spectra at high magnetic fields in Alcator C-Mod
Artikel i vetenskaplig tidskrift, 2018

In the Alcator C-Mod tokamak, runaway electron (RE) experiments have been performed during low density, ?attop plasma discharges at three magnetic felds: 2.7, 5.4, and 7.8 T, the last being the highest feld to-date at which REs have been generated and measured in a tokamak. Time-evolving synchrotron radiation spectra were measured in the visible wavelength range (λ∼300-1000 nm) by two absolutely-calibrated spectrometers viewing co- and counter-plasma current directions. In this paper, a test particle model is implemented to predict momentum-space and density evolutions of REs on the magnetic axis and q = 1, 3/2, and 2 surfaces. Drift orbits and subsequent loss of confnement are also incorporated into the evolution. These spatiotemporal results are input into the new synthetic diagnostic SOFT (Hoppe et al 2018 Nucl. Fusion 58 026032) which reproduces experimentally-measured spectra. For these discharges, it is inferred that synchrotron radiation dominates collisional friction as a power loss mechanism and that RE energies decrease as magnetic feld is increased. Additionally, the threshold electric feld for RE generation, as determined by hard x-ray and photo-neutron measurements, is compared to current theoretical predictions.

Tokamak plasma

runaway electron

synthetic diagnostic

synchrotron radiation

Författare

R. A. Tinguely

Massachusetts Institute of Technology (MIT)

R. S. Granetz

Massachusetts Institute of Technology (MIT)

Mathias Hoppe

Chalmers, Fysik, Subatomär fysik och plasmafysik

Ola Embréus

Chalmers, Fysik, Subatomär fysik och plasmafysik

Nuclear Fusion

0029-5515 (ISSN)

Vol. 58 7 076019

Skena och skina

Europeiska kommissionen (Horisont 2020), 2015-10-01 -- 2020-09-30.

Skenande elektroner i fusionsplasmor

Vetenskapsrådet (VR), 2015-01-01 -- 2018-12-31.

Ämneskategorier

Annan fysik

Fusion, plasma och rymdfysik

Den kondenserade materiens fysik

DOI

10.1088/1741-4326/aac444

Mer information

Senast uppdaterat

2018-09-19