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The relevance of inland waters in the global carbon cycle has been stressed recently, particularly because of a reassessment of their capacity for carbon exportation to the atmosphere and to the sediments. Global surveys have also highlighted the acute lack of information on tropical systems, which are exposed to crescent problems in the Global Change panorama, such as contamination and eutrophication, as well as important impacts related to water management strategies and water supply (e.g., water level fluctuations). Oxygen dynamics, a method left behind in the past, has been revised and is now being increasingly implemented to estimate primary production and ecosystemic respiration due to the urgency to understand carbon fluxes in aquatic systems. Therefore the details (advantages and disadvantages) of modern implementation of oxygen dynamics are revised and discussed here, particularly oriented to facilitate and promote their aplication in tropical aquatic systems (where it seems an adequate strategy). We suggest a unifying method pipeline in order to obtain comparable results among systems, towards the construction of a carbon flux inventory at larger (spatial and temporal) scales. This effort would contribute to understand the role and responses of tropical aquatic systems and regions (particularly as carbon sources or sinks) facing Global Change.

Plasma focus devices represent a class of hot and dense plasma sources that serve a dual role in fundamental plasma research and practical applications. These devices allow the observation of various phenomena, including the z-pinch effect, nuclear fusion reactions, plasma filaments, bursts, shocks, jets, X-rays, neutron pulses, ions, and electron beams. In recent years, considerable efforts have been directed toward miniaturizing plasma focus devices, driven by the pursuit of both basic studies and technological advancements. In this paper, we present the design and construction of a compact, portable pulsed plasma source based on plasma focus technology, operating at the ~2–4 Joule energy range for versatile applications (PF-2J: 120 nF capacitance, 6–9 kV charging voltage, 40 nH inductance, 2.16–4.86 J stored energy, and 10–15 kA maximum current at short circuit). The components of the device, including capacitors, spark gaps, discharge chambers, and power supplies, are transportable within hand luggage. The electrical characteristics of the discharge were thoroughly characterized using voltage and current derivative monitoring techniques. A peak current of 15 kiloamperes was achieved within 110 nanoseconds in a short-circuit configuration at a 9 kV charging voltage. Plasma dynamics were captured through optical refractive diagnostics employing a pulsed Nd-YAG laser with a 170-picosecond pulse duration. Clear evidence of the z-pinch effect was observed during discharges in a deuterium atmosphere at 4 millibars and 6 kilovolts. The measured pinch length and radius were approximately 0.8 mm and less than 100 μm, respectively. Additionally, we explore the potential applications of this compact pulsed plasma source. These include its use as a plasma shock irradiation device for analyzing materials intended for the first wall of nuclear fusion reactors, its capability in material film deposition, and its utility as an educational tool in experimental plasma physics. We also show its potential as a pulsed plasma thruster for nanosatellites, showcasing the advantages of miniaturized plasma focus technology. [ABSTRACT FROM AUTHOR]