Impact of triangularity on power sharing and boundary turbulence in TCV double-null L-mode plasmas

We present a systematic experimental study of triangularity effects on power sharing, Scrape-Off Layer (SOL) transport, and boundary turbulence in Double-Null (DN) L-mode plasmas in TCV. We show that triangularity (δ) strongly influences inner/outer power sharing between divertor targets. In high-δ DN plasmas (δ = 0.58), only 13% of the exhaust power reaches the inner targets, while in low-δ DN (δ = 0.17) this fraction rises to 28%. In Lower Single-Null plasmas, the inner target power fraction increases from 33% (δ = 0.58) to 48% (δ = 0.17). Comparisons with analytic models show that the observed power-sharing trends are qualitatively reproduced, and further suggest not only a reduction of poloidally ballooned radial transport, but also enhanced cross-field transport through the high-field side. While Thomson scattering measurements show no clear δ-dependence of midplane decay lengths, embedded Langmuir probes in the lower divertor shows a ∼ 59% broadening of λq∥ between δ = 0.17 and δ = 0.58. Finally, edge turbulence exhibit a 30% reduction in fluctuation levels at low δ. On a smaller scale, blob structures are 35% smaller in radial extent and with 43% lower amplitude with regard to the background values in low-δ DN compared to high-δ, in agreement with recent GBS simulations and supporting the correlation between plasma shaping, turbulence characteristics, and power sharing dynamics.