History of the Tromsø Ionosphere Heating facility

We present the historical background to the construction of a major ionospheric heating facility near Tromsø, Norway in the 1970s by the Max Planck Institute for Aeronomy and the subsequent operational history to the present. It was built next to the EISCAT incoherent scatter radar facility and in a region with a multitude of diagnostic instruments used to study the auroral region. The facility was transferred to the EISCAT Scientific Association in January 1993 and continues to provide new discoveries in plasma physics and ionospheric and atmospheric science to this day. It is expected that ‘Heating’ will continue operating together with the new generation of incoherent scatter radar, called EISCAT_3D, when it is commissioned in the near future.

Study of a Gas Disturbance Mode Content Based on the Measurement of Atmospheric Parameters at the Heights of the Mesosphere and Lower Thermosphere

The main result of this work is the estimation of the entropy mode accompanying a wave disturbance, observed at the atmosphere heights range of 90–120 km. The study is the direct continuation and development of recent results on diagnosis of the acoustic wave with the separation on direction of propagation. The estimation of the entropy mode contribution relies upon the measurements of the three dynamic variables (the temperature, density, and vertical velocity perturbations) of the neutral atmosphere measured by the method of the resonant scattering of radio waves on the artificial periodic irregularities of the ionospheric plasma. The measurement of the atmosphere dynamic parameters was carried out on the SURA heating facility. The mathematical foundation of the mode separation algorithm is based on the dynamic projection operators technique. The operators are constructed via the eigenvectors of the coordinate evolution operator of the transformed system of balance equations of the hydro-thermodynamics.

Sporadic E Layer with a Structure of Double Cusp in the Vertical Sounding Ionogram

In this study, we analyzed a large number of vertical sounding ionograms, obtained by the mid-latitude Cyclone ionosonde (55.85° N; 48.8° E) of Kazan (Volga Region) Federal University, which operates in a rapid-run mode of ionograms (1 ionogram per minute). Ionograms with a sporadic E layer type c, which have an unusual double cusp on the trace from the sporadic layer, were found among them. We attempted to simulate this unusual double cusp trace shape. Model calculations were performed to clarify the reasons for the appearance of the double cusp and to determine the shape of the lower part of the E and Es layers. The simulation was performed by fitting the profile of the electron densities of the E and Es layers, calculating the virtual reflection heights based on the refractive index using the Appleton-Hartree formula, and comparing them with the virtual heights of the layers on the ionogram. An estimate of the half-thickness of the lower part of the Es-layer was obtained. The possible reasons for the appearance of a trace with a double cusp of the Es layer are discussed. We assumed that the possible reasons for this phenomenon were the stratification of the E layer, and the interaction between the E and F layers in the form of descending or intermediate layers and atmospheric wave propagation. As an illustration of these phenomena, examples of an intermediate (descending) sporadic E layer and stratification of the E region and the Es layer are given according to observations of the lower ionosphere. These examples were obtained through the resonant scattering of probe radio waves by artificial periodic irregularities (API technique) of the ionospheric plasma, performed on the SURA mid-latitude heating facility (56.1° N; 46.1° E). The scattering of probe radio waves on the APIs generated by the heating facility made it possible to study various phenomena in the Earth’s ionosphere.

Perfection of technology and equipment for heating of steel ladles lining at horizontal stands

To change or repair sliding gates, steel ladles are installed in horizontal position, in which they are heated to keep a working temperature of lining. Peculiarities of a steel ladle heating in horizontal position considered. Description of the lining heating process presented, necessity of elaboration a method of its numeral simulation justified. The method should enable to make studies of influence of various methods of burner location on the ladle cover and torch parameters on efficiency of heating for a particular ladle and time available for the heating. A method of mathematical simulation of heat- and mass-exchange processes of lining heating in nonstationary conditions described. Based on examples of various variants of torch power calculation, dynamics of a ladle walls heating was shown. Results of calculation of temperature distribution over a ladle lining presented, as well as the map of gases flow in the ladle volume for various parameters of torch and heating process stages. Taking into consideration, that calculation costs related to simulation of nonstationary ladle heating are very high, a simplified one-dimensional model of calculation of lining heating process was elaborated. In the model correction factors are used, obtained as a result of numeral simulation. The model enables to make calculations in real time conditions and to use them for control at a practical steel ladle heating in horizontal position at a modern automized heating facility.

REMOTE DIAGNOSTICS OF EFFECTS INDUCED BY HIGH-LATITUDE HEATING FACILITIES

The results of long-term studies of the effects of the high-latitude ionosphere modification by powerful high-frequency (HF) radio waves generated by the EISCAT/Heating facility based on remote diagnostic methods are presented. The brief description of remote diagnostic instruments and methods is given. The excitation conditions and characteristics of small-scale artificial field-aligned irregularities induced by the O- and X-mode HF pumping are considered using the bi-static scatter method. The results of the spectral analysis of HF heater signals under various radiation modes are provided. It is shown that the X-mode HF pumping induces narrowband artificial radio emission of the ionosphere recorded at a distance of more than 1000 km from the heater.

SATELLITE OBSERVATIONS OF EFFECTS OF AURORAL IONOSPHERE HEATING WITH THE EISCAT FACILITY

The measurements are presented of the dynamics of energetic electrons on the Meteor-M No. 2 orbit during the experiment on the ionosphere heating by strong shortwave radiation with the EISCAT heating facility (Tromso, Norway) on October 12, 2018. It is revealed that the counting rate of electrons with energy >40 keV increased by five times in 30 s after the moment of the facility switch-off, and sharp (by 3–4 times) short counting rate peaks were registered as compared to the background. The peaks were repeated approximately every 6 seconds. The results of observations of variations in total electron content of the high-latitude ionosphere reconstructed from ionospheric delays of GLONASS R21 satellite signals during the same heating experiment are also presented. The analysis of these data revealed small exceeding of TEC values over the trend at the boundary of the heating area.

Mesospheric ozone in artificial modification of lower ionosphere.

We present some results of microwave observations of the middle atmosphere ozone under perturbation of the ionosphere by a power HF radio emission by the mid-latitude SURA heating facility (56N, 46E). New experiment was a continuation of studies to clarify the physical nature of the new phenomenon a decrease of the intensity of the microwave emission of the mesosphere in the ozone line when artificially impact on the lower ionosphere [1].

Generation of Internal Gravity Waves in the Thermosphere during Operation of the SURA Facility under Parametric Resonance Conditions

The problem of excitation of internal gravity waves (IGWs) in the upper atmosphere by an external source of a limited duration of operation is investigated. An isothermal atmosphere was chosen as the propagation environment of IGWs in the presence of a uniform wind that changes over time according to the harmonic law. For the vertical component of the displacement of an environment, the Mathieu equation with zero initial conditions was solved with the right part simulating the effect of a powerful heating facility on the ionosphere. In the case of a small amplitude of the variable component of the wind, the time dependence of the vertical displacement under parametric resonance conditions using the perturbation method is obtained. The obtained dependence of the solution of the differential equation on the parameters allows us to perform a numerical analysis of the problem in the case of variable wind of arbitrary amplitude. For practical estimations of the obtained values, data on the operating modes of the SURA heating facility (56.15° N, 46.11° E) with periodic (15–30 min) switching on during of 2–3 h for ionosphere impact were used.