Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: MHD simulations of small ELMs at low triangularity in ASDEX Upgrade   The development of small- and no-ELM regimes for ITER is a high priority
topic due to the risks associated to type-I ELMs. By considering non-linear
extended MHD simulations of the ASDEX Upgrade tokamak with the JOREK code, we
probe a regime that avoids type-I ELMs completely provided that the separatrix
density is high enough. The dynamics of the pedestal in this regime are
observed to be qualitatively similar to the so-called quasi-continuous exhaust
(QCE) regime in several ways. Repetitive type-I ELMs are substituted by roughly
constant levels of outwards transport caused by peeling-ballooning modes (with
dominant ballooning characteristics) which are localised in the last 5\% of the
confined region (in normalised poloidal flux). The simulated low triangularity
plasma transitions to a type-I ELMy H-mode if the separatrix density is
sufficiently reduced or if the input heating power is sufficiently increased.
The stabilising factors that play a role in the suppression of the small ELMs
are also investigated by analysing the simulations, and the importance of
including diamagnetic effects in the simulations is highlighted. By considering
a scan in the pedestal resistivity and by measuring the poloidal velocity of
the modes (and comparing to theoretical estimates for ideal and resistive
modes), we identify the underlying instabilities as resistive
peeling-ballooning modes. Decreasing the resistivity below
experimentally-relevant conditions (i.e., going towards ideal MHD), the
peeling-ballooning modes that constrain the pedestal below the type-I ELM
stability boundary display sharply decreasing growth rates.

11
The categories of this paper are: hep-lat
36
The categories of this paper are: cmp-lg
35
The categories of this paper are: mtrl-th
21
The categories of this paper are: adap-org
27
The categories of this paper are: comp-gas
5
The categories of this paper are: gr-qc
19
The categories of this paper are: eess
13
The categories of this paper are: quant-ph
37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga
18
The categories of this paper are: econ
30
The categories of this paper are: q-alg
9
The categories of this paper are: nlin
34
The categories of this paper are: chem-ph
12
The categories of this paper are: nucl-th
7
The categories of this paper are: hep-th