Evaluation of ambipolar potential barrier in the gas dynamic trap by Doppler spectroscopy

The recently developed Doppler spectroscopy diagnostic has been used to evaluate the height of the ambipolar potential barrier forming in the gas dynamic trap (GDT) plasma between the central cell and the region with a large magnetic expansion ratio beyond the mirror. The diagnostic technique based on the gas jet charge exchange target, allowed to measure the potential profile along the line of sight covering the radial range from the axis to the limiter. The on-axis potential drop was found to be 2.6÷3.1 in units of the central plane electron temperature, which supports the existing theoretical understanding of suppression of electron thermal conductivity in the GDT expander.

A Hot Mars-sized Exoplanet Transiting an M Dwarf

We validate the planetary nature of an ultra-short-period planet orbiting the M dwarf KOI-4777. We use a combination of space-based photometry from Kepler, high-precision, near-infrared Doppler spectroscopy from the Habitable-zone Planet Finder, and adaptive optics imaging to characterize this system. KOI-4777.01 is a Mars-sized exoplanet (R p = 0.51 ± 0.03R ⊕) orbiting the host star every 0.412 days (∼9.9 hr). This is the smallest validated ultra-short period planet known and we see no evidence for additional massive companions using our HPF RVs. We constrain the upper 3σ mass to M p < 0.34 M ⊕ by assuming the planet is less dense than iron. Obtaining a mass measurement for KOI-4777.01 is beyond current instrumental capabilities.

Development of the method of laser Doppler spectroscopy of nanoparticles in liquids and implementation of the method in the LAD-079 spectrometer

In this work, a method for physicochemical and biological optical studies of the nanoparticles size distribution is developed. Its implementation in the LAD-079 spectrometer is described. The distinctive features of the LAD-079 spectrometer include the following. Multi-angle parallel measurements of static and dynamic light scattering, scattering angle from 0–180 degrees. Probing at three wavelengths with the ability to analyze the polarization activity of the sample (488 nm, 532 nm, 650 nm). Programmable precision thermostat with an error less than 0.1 °C in the range 0 ÷ +80°C with the possibility of building and software implementation of the experiment plan. Robust monobloc design of the spectrometer that does not require adjustments and a special optical table. The ability to measure the size of dispersed nanoparticles in low-transparent liquids.

Preparation of human biological fluid for studies by Laser Doppler Spectroscopy

The paper presents a method for preparing the human biological fluid by the example of urine specimen for studies by Laser Doppler Spectroscopy. The time and storage conditions of the specimen acceptable for correct research are determined. The optimal parameters for measuring and calculating dimensions - temperature, viscosity, refractive index – are identified. The need to filter samples before testing is noted. The centrifugation parameters are determined.