Study Of Atmospheric Phenomena Research Articles

Mini-EUSO on Board the International Space Station: Mission Status and Results

The telescope Mini-EUSO has been observing, since 2019, the Earth in the ultraviolet band (290–430 nm) through a nadir-facing UV-transparent window in the Russian Zvezda module of the International Space Station. The instrument has a square field of view of 44°, a spatial resolution on the Earth surface of 6.3 km and a temporal sampling rate of 2.5 microseconds. The optics is composed of two 25 cm diameter Fresnel lenses and a focal surface consisting of 36 multi-anode photomultiplier tubes, 64 pixels each, for a total of 2304 channels. In addition to the main camera, Mini-EUSO also contains two cameras in the near infrared and visible ranges, a series of silicon photomultiplier sensors and UV sensors to manage night-day transitions. Its triggering and on-board processing allow the telescope to detect UV emissions of cosmic, atmospheric and terrestrial origin on different time scales, from a few microseconds up to tens of milliseconds. This makes it possible to investigate a wide variety of events: the study of atmospheric phenomena (lightning, transient luminous events (TLEs) such as ELVES and sprites), meteors and meteoroids; the search for nuclearites and strange quark matter; and the observation of artificial satellites and space debris. Mini-EUSO is also potentially capable of observing extensive air showers generated by ultra-high-energy cosmic rays with an energy above 1021 eV and can detect artificial flashing events and showers generated with lasers from the ground. The instrument was integrated and qualified in 2019 in Rome, with additional tests in Moscow and final, pre-launch tests in Baikonur. Operations involve periodic installation in the Zvezda module of the station with observations during the crew night time, with periodic downlink of data samples, and the full dataset being sent to the ground via pouches containing the data disks. In this work, the mission status and the main scientific results obtained so far are presented, in light of future observations with similar instruments.

On the Kinetic Features of Sedimentation of Dust Particles in the Martian Atmosphere

The mode of subsidence of layered structures in the ionosphere of Mars has been studied taking into account the compositional features of the Martian atmosphere. The characteristic sedimentation rates of dust particles, their sizes and charges, as well as the sedimentation time of layered structures are calculated. The results obtained can be used in the study of atmospheric phenomena on Mars in the course of upcoming space missions.

A Multi-Frequency Terahertz Quantum-Cascade Laser for Atmospheric Probing and Detection of Small Impurities

A multi-frequency terahertz radiation source based on quantum-cascade lasers is described. The prospects of its application for the study of atmospheric phenomena and the creation of lidars and remote sensing equipment are discussed. The influence of radiation attenuation in the atmosphere for three frequency ranges was studied using the proposed terahertz source. Estimates of the influence of the laser spectral line width on terahertz radiation attenuation coefficient measurements in the atmosphere were obtained.

The use of finite-element based programs in the study of atmospheric phenomena

The academic problem described in this paper concerns the measures to protect an idealized building against atmospheric discharges. The proposed lightning protection system contains a Franklin rod and two down conductors connected to the ground. The problem is analyzed computationally employing a two-dimensional finite element program. Two numerical models are used to investigate the distributions of electric potential and electric field around the building. Numerical results show that, by using the proposed lightning protection system, the mean value of the electric field close to the building increases more than four times. The paper also presents a theoretical description on fair-weather and storm conditions.

The South America VLF NETwork (SAVNET)

In this paper we present the South America VLF NETwork (SAVNET), a new observing facility at very low frequencies. It has been recently installed at different locations spread over Latin America, in Brazil, Peru and Argentina. It consists of a network of seven Very Low Frequency (VLF) receivers with the main scientific objective of monitoring the solar activity on short (minutes to hours) and long (years) time scales. Other objectives include a better understanding of the spatial structure of the South Atlantic Magnetic Anomaly, the study of atmospheric phenomena and the search for genuine seismic-electromagnetic effects. After discussing the scientific goals, the details of the installation are presented as well as the first results recently obtained.

Mesoscale Dynamics

Mesoscale meteorology is the study of atmospheric phenomena with typical spatial scales between 10 and 1000 kilometers. Examples of mesoscale phenomena include fronts, mesoconvective systems, thunderstorms, gap winds, downslope windstorms, and land‐sea breezes. Many of the weather phenomena that most directly affect human activity occur on the mesoscale.While researchers have been able to successfully predict large‐scale weather patterns since the 1950s, the prediction of smaller—or mesoscale—phenomena such as storms has proven more difficult. Why the lag in mesoscale prediction? The dynamics of weather phenomena on large scales can largely be described by considering just hydrostatic and geostrophic balance, allowing them to be described by highly simplified models.

A cloud chamber control system

We describe an analog control system for the temperature control of an expansion cloud chamber. During the expansion, the sample gas and the chamber walls are cooled at the same rate so as to maintain adiabaticity. The control system measures the wall temperature with transistor temperature sensors, calculates the gas temperature from the gas pressure using the adiabatic gas law, and generates a control signal proportional to their difference. The control precision is sufficient to allow the chamber to be used in the study of atmospheric phenomena.