scholarly journals Laser induced fluorescence measurements of axial velocity, velocity shear, and parallel ion temperature profiles during the route to plasma turbulence in a linear magnetized plasma device

2016 ◽  
Vol 87 (11) ◽  
pp. 11E513 ◽  
Author(s):  
S. Chakraborty Thakur ◽  
K. Adriany ◽  
J. J. Gosselin ◽  
J. McKee ◽  
E. E. Scime ◽  
...  
Keyword(s):  
Axial Velocity ◽  
Plasma Turbulence ◽  
Laser Induced Fluorescence ◽  
Magnetized Plasma ◽  
Velocity Shear ◽  
Temperature Profiles ◽  
Ion Temperature ◽  
Fluorescence Measurements ◽  
Plasma Device

scholarly journals Enstrophy non-conservation and the forward cascade of energy in two-dimensional electrostatic magnetized plasma turbulence

2020 ◽  
Vol 86 (4) ◽  
Author(s):  
G. G. Plunk
Keyword(s):  
Temperature Gradient ◽  
Plasma Turbulence ◽  
Magnetized Plasma ◽  
Larmor Radius ◽  
Ion Temperature ◽  
Fluid System ◽  
Ion Temperature Gradient ◽  
Zonal Flows ◽  
Electron Temperature Gradient ◽  
Enstrophy Cascade

A fluid system is derived to describe electrostatic magnetized plasma turbulence at scales somewhat larger than the Larmor radius of a given species. It is related to the Hasegawa–Mima equation, but does not conserve enstrophy, and, as a result, exhibits a forward cascade of energy, to small scales. The inertial-range energy spectrum is argued to be shallower than a $-11/3$ power law, as compared to the $-5$ law of the Hasegawa–Mima enstrophy cascade. This property, confirmed here by direct numerical simulations of the fluid system, may help explain the fluctuation spectrum observed in gyrokinetic simulations of streamer-dominated electron-temperature-gradient driven turbulence (Plunk et al., Phys. Rev. Lett., vol. 122, 2019, 035002), and also possibly some cases of ion-temperature-gradient driven turbulence where zonal flows are suppressed (Plunk et al., Phys. Rev. Lett., vol. 118, 2017, 105002).

Monitoring of cold and light stress impact on photosynthesis by using the laser induced fluorescence transient (LIFT) approach

2010 ◽  
Vol 37 (5) ◽  
pp. 395 ◽  
Author(s):  
Roland Pieruschka ◽  
Denis Klimov ◽  
Zbigniew S. Kolber ◽  
Joseph A. Berry
Keyword(s):  
Photosynthetic Efficiency ◽  
Light Stress ◽  
Pulse Amplitude ◽  
Laser Induced Fluorescence ◽  
High Light Intensity ◽  
High Light ◽  
Persea Americana ◽  
Effective Quantum Yield ◽  
Fluorescence Transient ◽  
Fluorescence Measurements

Chlorophyll fluorescence measurements have been widely applied to quantify the photosynthetic efficiency of plants non-destructively. The most commonly used pulse amplitude modulated (PAM) technique provides a saturating light pulse, which is not practical at the canopy scale. We report here on a recently developed technique, laser induced fluorescence transient (LIFT), which is capable of remotely measuring the photosynthetic efficiency of selected leaves at a distance of up to 50 m. The LIFT approach correlated well with gas exchange measurements under laboratory conditions and was tested in a field experiment monitoring the combined effect of low temperatures and high light intensity on a variety of plants during the early winter in California. We observed a reduction in maximum and effective quantum yield in electron transport for Capsicum annuum L., Lycopersicon esculentum L. and Persea americana Mill. as the temperatures fell, while a grass community was not affected by combined low temperature and high light stress. The ability to make continuous, automatic and remote measurements of the photosynthetic efficiency of leaves with the LIFT system provides a new approach for studying and monitoring of stress effects on the canopy scale.

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