Geomagnetic Radiation Research Articles

Signal model and event reconstruction for the radio detection of inclined air showers

The detection of inclined air showers (zenith angles θ ≳ 65°) with kilometer-spaced radio-antenna arrays allows measuring cosmic rays at ultra-high energies (E ≲ 1020 eV). Radio and particle detector arrays provide independent measurements of the electromagnetic and muonic shower components of inclined air showers, respectively. Combined, these measurements have a large sensitivity to discriminate between air showers initiated by lighter and heavier cosmic rays. We have developed a precise model of the two-dimensional, highly complex and asymmetric lateral radio-signal distributions of inclined air shower at ground — the “radio-emission footprints”. Our model explicitly describes the dominant geomagnetic emission with a rotationally symmetric lateral distribution function, on top of which additional effects disturb the symmetry. The asymmetries are associated with the interference between the geomagnetic and sub-dominant charge-excess emission as well as with geometrical projection effects, so-called “early-late” effects. Our fully analytic model describes the entire footprint with only two observables: the geometrical distance between the shower impact point at the ground and the shower maximum d max, and the geomagnetic radiation energy E geo. We demonstrate that with this model, the electromagnetic shower energy can be reconstructed by kilometer-spaced antenna arrays with an intrinsic resolution of 5% and a negligible bias.

Analysis of efficiency and quality of filters suppressing RFI in radio detection of cosmic rays

Radio stations of the Auger Engineering Radio Array (AERA) investigates radio signals from coherent emissions due to geomagnetic radiation and charge excess processes. The frequency band is limited to 30–80 MHz. In order to improve the signal to noise ratio, RFI filters have to be used to suppress this contamination.The paper compares several (currently in use and proposed) RFI filters. We analyzed: the non-adaptive filter (IIR notch) as well as adaptive filters: IIR notch supported by the virtual NIOS® processor, FIR based on the linear prediction supported by the virtual NIOS® processor and finally the Least Mean Square filter. The LMS filter proposed for the RFI suppression should use correct learning factor, crucial for a stability of the filter, which could be determined by eigenvalues of the auto-correlation matrix built for ADC samples.For typical AERA configuration (4 beacons with fixed frequencies) the best filter seems to be the IIR as introducing very high suppression efficiency with relatively low distortions and low energy consumption. However, when unexpected RFI appears it is worth consider a combination of fixed frequency IIR + IIR filter supported with NIOS processor identifying additional RFI source as well as FIR filters. LMS filters can be used when very fast response on new sources is needed.

Stable convergence of the algorithm computing the coefficients of the LMS filter suppressing RFI in radio detection of cosmic rays in the Auger Engineering Radio Array

Radio stations of the Auger Engineering Radio Array (AERA) investigates radio signals from coherent emissions due to geomagnetic radiation and charge excess processes. The frequency band is limited to 30–80 MHz. This range is highly contaminated by human-made RFI. In order to improve the signal to noise ratio, RFI filters have to be used to suppress this contamination.The LMS filter proposed for the RFI suppression should use correct learning factor, crucial for a stability of the filter, which could be determined by eigenvalues of the auto-correlation matrix built for ADC samples.A detailed analysis of almost one million of AERA events confirms that eigenvalues of real cosmic events taken from the AERA database fully allow their use in the LMS filters, with learning factors optimal for the most efficient RFI suppression.This type of the filter can be used in other radio cosmic ray experiments e.g. the Giant Radio Array for Neutrino Detection (GRAND).

Filters for RFI suppression in AERA radio detection of cosmic rays

Radio stations can observe radio signals caused by coherent emissions due to geomagnetic radiation and charge excess processes mainly in the frequency band from 30 to 80 MHz. This range is often highly contaminated by human-made RFI. In order to improve the signal to noise ratio, RFI filters have to suppress this contamination.The paper compares several (currently in use and proposed) RFI filters used in the Auger Engineering Radio Array (AERA), being a part of the Pierre Auger Observatory. We analyzed both: the non-adaptive filter (IIR notch) as well as adaptive filters: IIR notch supported by the virtual NIOS® processor, FIR based on the linear prediction supported by the virtual NIOS® processor, the FIR fully implemented into FPGA fabric used the Levinson algorithm without any processor (all coefficients fully calculated in the FPGA logic elements) and finally the Delayed Least Mean Square filter also with a modification proposed by Harris, variable step size and Instantaneous LMS filter.We investigated: the efficiency of the several mono-carriers suppression, the distortion factors of cosmic rays pulses after filtering, the speed of the filter response as well as the power consumption crucial for systems supplied by solar panels.The 200 MW solar farm with 250 kV power line is anticipated to be built in the Southern part of the Auger array. High-power DC/AC converter for sure introduce a huge noise in the electromagnetic spectrum being a topic of interest of AERA. Very efficient, adaptive filter becomes a crucial issue. Simulations and laboratory measurement suggest that the most promising will be the Instantaneous Least Mean Square filter with dynamically modified input range.

Effect of Simulated Geomagnetic Activity on Myocardial Ischemia/Reperfusion Injury in Rats.

ObjectiveTo study the response of myocardial ischemia/reperfusion injury (MI/RI) in rats to simulated geomagnetic activity.MethodsIn a simulated strong geomagnetic outbreak, the MI/RI rat models were radiated, and their area of myocardial infarction, hemodynamic parameters, creatine kinase (CK), lactate dehydrogenase (LDH), melatonin, and troponin I values were measured after a 24-hour intervention.ResultsOur analysis indicates that the concentrations of troponin I in the geomagnetic shielding+operation group were lower than in the radiation+operation group (P<0.05), the concentrations of melatonin in the shielding+operation group and normal+operation group were higher than in the radiation + operation group (P<0.01), and the concentrations of CK in the shielding + operation group were lower than in the radiation + operation group and normal + operation group (P<0.05). Left ventricular developed pressure (LVDP) and ± dP/dtmax in the radiation+operation group were lower than in the shielding + operation group and normal+operation group (P<0.01). Left ventricular end-diastolic pressure (LEVDP) in the shielding + operation group was higher than in the normal + operation group (P<0.05). There was no significant difference in area of myocardial infarction and LDH between the shielding + operation group and the radiation + operation group.ConclusionOur data suggest that geomagnetic activity is important in regulating myocardial reperfusion injury. The geomagnetic shielding has a protective effect on myocardial injury, and the geomagnetic radiation is a risk factor for aggravating the cardiovascular and cerebrovascular diseases.

Adaptive IIR-Notch Filter for RFI Suppression in a Radio Detection of Cosmic Rays

Radio stations can observe radio signals caused by coherent emissions due to geomagnetic radiation and charge excess processes mainly in the frequency band from 30 to 80 MHz. This range is highly contaminated by human-made radio frequency interference (RFI). In order to improve the signal-to-noise ratio, RFI filters are used to suppress this contamination. Infinite impulse response (IIR)-notch filters operate with fixed parameters and suppress several narrow bands. IIR filters are generally potentially unstable due to feedbacks; however, they are much shorter and more power efficient than finite impulse response filters. We implemented an NIOS virtual processor calculating new set of IIR filter coefficients, which are reloaded dynamically on-the-fly. Spectrum analysis of the 30–80-MHz band can also be supported by the Altera IP Cores. The NIOS adjusts the new coefficients of the filter checking whether the poles are inside the unique complex radius (a condition of stability) as well as tuning the width of the notch filter. Practical implementation was tested in the laboratory with signal and pattern generators. Laboratory results are very promising. The IIR filter follows the drifting frequencies over very wide ranges (even 15 MHz for investigated range of 30–80 MHz), keeping a suppression factor on a very high level (≥10). The novelty of this paper is an introduction of the adaptive IIR-notch filter, which has not been used in any previous experiment.

Towards real-time identification of cosmic rays with LOw-Frequency ARray radio antennas

Cosmic rays entering the Earth’s atmosphere produce Extensive Air Showers, which emit a radio signal through Geo-magnetic radiation and Askaryan emission. At the present time, one of the biggest challenges for assessing the Radio detection as a valuable technique for Cosmic-ray observation is to identify in real-time the very short (less than 100 ns) radio signals over the background noise. In this work, we present the latest updates on the real-time identification of radio signals from Extensive Air Showers by using the data from LOFAR Low Band Antenna stations, which are sensitive in the 30-80 MHz region.

Adaptive Linear Predictor FIR Filter Based on the Cyclone V FPGA With HPS to Reduce Narrow Band RFI in Radio Detection of Cosmic Rays

We are presenting a new approach to a filtering of radio frequency interference (RFI) in the Auger Engineering Radio Array (AERA), which studies the electromagnetic part of the extensive air showers. Radio stations can observe radio signals caused by coherent emissions due to geomagnetic radiation and charge excess processes. AERA observes the frequency band from 30 to 80 MHz. This range is highly contaminated by human-made RFI. In order to improve the signal to noise ratio RFI filters are used in AERA to suppress this contamination. The filter has already been tested with real AERA radio stations in the Argentinean Pampas with very successful results. The linear equations were solved either in the virtual soft-core NIOS® processor (implemented in the FPGA chip as a net of logic elements) or in the external Voipac PXA270M ARM processor. The NIOS® processor is relatively slow (50 MHz internal clock), and the calculations performed in an external processor consume a significant amount of time for data exchange between the FPGA and the processor. Tests showed very good efficiency of the RFI suppression for stationary (long-term) contaminations. However, we observed short-time contaminations, which could not be suppressed either by the IIR-notch filter or by the FIR filter based on the linear predictions. For the LP FIR filter, the refresh time of the filter coefficients was too long and the filter did not keep up with the changes in the contamination structure, mainly due to a long calculation time in a slow processors. We propose to use the Cyclone® V SE chip with an embedded micro-controller operating with a 925 MHz internal clock to significantly reduce the refreshment time of the FIR coefficients. First results in the laboratory are very promising.

Using orbital tethers to remediate geomagnetic radiation belts

AbstractThe Van Allen radiation belts pose a hazard to spacecraft and astronauts, and similar radiation belts around other planets pose a hazard to interplanetary probes. We discuss a method of remediating these radiation belts first proposed by Danilov and Vasilyev, and recently improved by Hoyt, Minor, and Cash, where a long, charged tether is placed in orbit inside a radiation belt. In this approach, an electric field of the tether scatters the belt particles into a pitch angle loss cone leading to absorption of the particles in the atmosphere. A test particle calculation is presented which computes the scattered pitch angle of belt particles as a function of initial pitch angle and gyrophase for different particle energies. The moments of the resulting distribution of scattered angle versus initial pitch angle are used to compute the number density of the belt as a function of time using a Fokker‐Planck diffusion approximation. Finally, we use the characteristic timescales of scattering for particles of different energies to discuss the feasibility of using such a system of tethers as a long and short‐term remediation solution.

FPGA Based Wavelet Trigger in Radio Detection of Cosmic Rays

Experiments which show coherent radio emission from extensive air showers induced by ultra-high-energy cosmic rays are designed for a detailed study of the development of the electromagnetic part of air showers. Radio detectors can operate with 100 % up time as, e.g., surface detectors based on water-Cherenkov tanks. They are being developed for ground-based experiments (e.g., the Pierre Auger Observatory) as another type of air-shower detector in addition to fluorescence detectors, which operate with only ∼10 % of duty on dark nights. The radio signals from air showers are caused by coherent emission from geomagnetic radiation and charge-excess processes. The self-triggers in radio detectors currently in use often generate a dense stream of data, which is analyzed afterwards. Huge amounts of registered data require significant manpower for off-line analysis. Improvement of trigger efficiency is a relevant factor. The wavelet trigger, which investigates on-line the power of radio signals (∼V2/R), is promising; however, it requires some improvements with respect to current designs. In this work, Morlet wavelets with various scaling factors were used for an analysis of real data from the Auger Engineering Radio Array and for optimization of the utilization of the resources in an FPGA. The wavelet analysis showed that the power of events is concentrated mostly in a limited range of the frequency spectrum (consistent with a range imposed by the input analog band-pass filter). However, we found several events with suspicious spectral characteristics, where the signal power is spread over the full band-width sampled by a 200 MHz digitizer with significant contribution of very high and very low frequencies. These events may not originate from cosmic ray showers but could be the result of human contamination. The engine of the wavelet analysis can be implemented in the modern powerful FPGAs and can remove suspicious events on-line to reduce the trigger rate.

An Optimization of the FPGA Based Wavelet Trigger in Radio Detection of Cosmic Rays

Experiments that observe coherent radio emission from extensive air showers induced by ultra-high energy cosmic rays are designed for a detailed study of the development of the electromagnetic part of air showers. Radio detectors can operate with 100% up time as e.g. surface detectors based on water-Cherenkov tanks. They are being developed for ground-based experiments (e.g. the Pierre Auger Observatory) as another type of air shower detector in addition to the fluorescence detectors, which operate with only ~10% of duty in dark nights. The radio signals from air showers are caused by the coherent emission due to geomagnetic radiation and charge excess processes. Currently used self-triggers in radio detectors often generate a dense stream of data, which is analyzed afterwards. Huge amounts of registered data requires a significant man-power for the off-line analysis. An improvement of the trigger efficiency becomes a relevant factor. In this work, Morlet wavelets with various scaling factors were used for an analysis of real data from the Auger Engineering Radio Array and for an optimization of the utilization of the resources in an FPGA. The wavelet analysis showed that the power of events is concentrated mostly in a limited range of the frequency spectrum (consistent with a range imposed by the input analog band-pass filter). However, we found several events with suspicious spectral characteristics, where the signal power is spread over the full band-width sampled by a 200 MHz digitizer with significant contribution of very high and very low frequencies. These events may not origin from cosmic ray showers but can be human-made contaminations. The engine of the wavelet analysis can be implemented into the modern powerful FPGA and can remove suspicious events on-line to reduce the trigger rate.

Recent results from cosmic-ray measurements with LOFAR

LOFAR, the Low Frequency Array, is currently the world's largest distributed radio telescope observing at frequencies below 240MHz. LOFAR is measuring cosmic-ray induced air-showers since June 2011 and has collected several hundreds of events with hundreds of antennas per individual event. We present measurements of the radio signal strength as well as high-precision measurements of wavefront curvature and polarization. These will enable us to disentangle the different emission mechanisms at play, such as geomagnetic radiation, charge excess, and Askaryan or Cherenkov effects, leading to a full understanding of the air-shower radio emission. Furthermore we give a first example on how the full complexity of the signal enables radio measurements to be used to study primary particle composition.

Influence of circadian rhythms of the geomagnetic field and cosmic background radiation on nitric oxide generation in the human body

Circadian rhythms of background gamma radiation and the Ki indices of the geomagnetic field (GMF) in August-September 2008, January-February 2010, and March 2011 have been studied. It has been demonstrated that in the summer period, the maximum radiation and increase in GMF activity have been observed at about 15:00 LT. In winter these maximums are synchronously shifted to a later time. It is assumed that in response to the background radiation and as a consequence the formation of free radicals, the body generates its own free radicals for their neutralization, such as nitric oxide, which form due to the cleavage of blood neutrophils with a decrease in GMF activity. In turn, the nitric oxide level in the body is regulated by the formation of melatonin, which has a pronounced circadian rhythm.

Impact of the geomagnetic field and solar radiation on climate change

Recent studies have shown that, in addition to the role of solar variability, past climate changes may have been connected with variations in the Earth’s magnetic field elements at various timescales. An analysis of variations in geomagnetic field elements, such as field intensity, reversals, and excursions, allowed us to establish a link between climate changes at various timescales over the last millennia. Of particular interest are sharp changes in the geomagnetic field intensity and short reversals of the magnetic poles (excursions). The beginning and termination of the examined geomagnetic excursions can be attributed to periods of climate change. In this study, we analyzed the possible link between short-term geomagnetic variability (jerks) and climate change, as well as the accelerated drift of the north magnetic pole and surface temperature variations. The results do not rule out the possibility that geomagnetic field variations which modulate the cosmic ray flux could have played a major role in climate change in addition to previously induced by solar radiation.

A Dynamic Model for the Validation of Cosmic Rays Anisotropy at Low Earth Orbit

The International Space Station (ISS) provides the proving ground for future long duration human activities in space. Ionizing radiation measurements at low Earth orbit (LEO) in general, and at ISS in particular, form the ideal tool for the experimental validation of radiation environmental models, nuclear transport code algorithms and nuclear reaction cross sections. Indeed, prior measurements onboard the space transportation system (STS; shuttle) have provided vital information impacting both the environmental models and the nuclear transport code development by requiring dynamic (time dependent) models of the LEO environment. In addition, past studies using computer aided design (CAD) models of ISS have demonstrated that the ion specific based flux or cumulative based dose exposure prediction for a spacecraft at LEO requires the description of an environmental model with accurate anisotropic (directional) as well as dynamic behavior. Within the framework of an environment code named GEORAD (GEOmagnetic RADiation), this paper describes the dynamic and anisotropic capabilities of GEORAD as applied to the interaction of galactic cosmic rays (GCR) with the geomagnetic field at LEO. The described model is a component of GEORAD which computes anisotropic cutoff rigidity and the corresponding transmission coefficient, both of which are used as input into a deterministic particle transport algorithm for exposure estimation within ISS. The GEORAD capability to compute anisotropic cutoff rigidity and transmission coefficient provides a useful tool to validate GCR exposure measurements by solid state particle telescopes which inherently have strong directional sensitivity. While this paper concentration is on the anisotropic characteristics of GCR ions at LEO, GEORAD suite is applicable to radiation environment prediction at LEO, medium Earth orbit (MEO) and geosynchronous Earth orbit (GEO) at quiet solar periods. GEORAD interest is in the study of the geomagnetic environment from a long term point of view (i.e., a meaningful portion of solar cycle), and therefore it does not account for any short term distortion of the geomagnetic field due to solar activity. With the concentration of the paper on the study of GCR ions at LEO, for the formation flying ISS, the paper presents the anisotropic profile of GCR ions at different angular distribution with respect to zenith. While the magnitude of the GCR anisotropy at LEO depends on a multitude of factors such as the ions rigidity, transmission, attitude and orientation of the spacecraft along the velocity vector, the paper draws quantitative conclusions on the effect of GCR anisotropy at LEO.

A low earth orbit dynamic model for the proton anisotropy validation

Ionizing radiation measurements at low earth orbit (LEO) form the ideal tool for the experimental validation of radiation environmental models, nuclear transport code algorithms and nuclear reaction cross sections. Indeed, prior measurements on the space transportation system (STS; shuttle) have provided vital information impacting both the environmental models and the nuclear transport code development by requiring dynamic models of the LEO environment. Previous studies using computer aided design (CAD) models of the international space station (ISS) have demonstrated that the dosimetric prediction for a spacecraft at LEO requires the description of an environmental model with accurate anisotropic as well as dynamic behavior. This paper describes such a model for the trapped proton. The described model is a component of a suite of codes collectively named GEORAD (GEOmagnetic RADiation) which computes cutoff rigidity, trapped proton and trapped electron environments. The web version of GEORAD is named OLTARIS (On-line Tool for the Assessment of Radiation in Space). GEORAD suite is applicable to radiation environment prediction at LEO, medium earth orbit (MEO) and geosynchronous earth orbit (GEO) at quiet solar periods. GEORAD interest is in the study of long term effect of the trapped environment and therefore it does not account for any short term external field contribution due to solar activity. With the concentration of the paper on the LEO protons only, the paper presents the validation of the trapped proton model within GEORAD with reported measurements from the compact environment anomaly sensor (CEASE) science instrument package, flown onboard the tri-service experiment-5 (TSX-5) satellite during the period of June 2000 to July 2006. The spin stabilized satellite was flown in a 410 × 1710 km, 69° inclination elliptical orbit, allowing it to be exposed to a broad range of the LEO regime. The paper puts particular emphasize on the validation of the differential at 40 MeV, and integral at >40 MeV proton flux profiles, in the vicinity of the south Atlantic anomaly (SAA) region where protons exhibit east–west (EW) anisotropy and have a relatively narrow pitch angle distribution. Within SAA, the EW anisotropy results in different level of exposure to different sections of a formation flying spacecraft such as TSX-5 or ISS. While the magnitude of the EW effect at LEO depends on a multitude of factors such as trapped proton energy, orientation of the spacecraft along the velocity vector and altitude of the spacecraft, the paper draws quantitative conclusions on the combined effect of proton pitch angle and EW anomaly.

The Low Earth Orbit validation of a dynamic and anisotropic trapped radiation model through ISS measurements

The International Space Station (ISS) provides the proving ground for future long duration human activities in space. Ionizing radiation measurements in ISS form the ideal tool for the experimental validation of radiation environmental models, nuclear transport code algorithms and nuclear reaction cross sections. Indeed, prior measurements on the Space Transportation System (STS; Shuttle) have provided vital information impacting both the environmental models and the nuclear transport code development by requiring dynamic models of the Low Earth Orbit (LEO) environment. Previous studies using Computer Aided Design (CAD) models of the evolving ISS configurations with Thermo-Luminescent Detector (TLD) area monitors, demonstrated that computational dosimetry requires environmental models with accurate non-isotropic as well as dynamic behavior, detailed information on rack loading, and an accurate six degree of freedom (DOF) description of ISS trajectory and orientation. It is imperative that we understand ISS exposures dynamically for crew career planning, and insure that the regulatory requirements of keeping exposure as low as reasonably achievable (ALARA) are adequately implemented. This is especially true as ISS nears some form of completion with increasing complexity, resulting in a larger drag coefficient, and requiring operation at higher altitudes with increased exposure rates. In this paper ISS environmental model is configured for 11A (circa mid 2005), and uses non-isotropic and dynamic geomagnetic transmission and trapped proton models. ISS 11A and LEO model validations are important steps in preparation for the design and validation for the next generation manned vehicles. While the described cutoff rigidity, trapped proton and electron formalisms as coded in a package named GEORAD (GEOmagnetic RADiation) and a web interface named OLTARIS (On-line Tool for the Assessment of Radiation in Space) are applicable to the LEO, Medium Earth Orbit (MEO) and Geosynchronous Earth Orbit (GEO) at quiet solar periods, in this report, the validation of the models using available measurements are limited to STS and ISS nominal operational altitudes (300–400 km) range at LEO where the dominant fields within the vehicle are the trapped proton and attenuated Galactic Cosmic Ray (GCR) ions. The described formalism applies to trapped electron at LEO, MEO and GEO as well. Due to the scarcity of available electron measurements, the trapped electron capabilities of the GEORAD are not discussed in this report, but are accessible through OLTARIS web interface. GEORAD and OLTARIS interests are in the study of long term effects (i.e. a meaningful portion of solar cycle). Therefore, GEORAD does not incorporate any short term external field contribution due to solar activity. Finally, we apply these environmental models to selected target points within ISS 6A (circa early 2001), 7A (circa late 2001), and 11A during its passage through the South Atlantic Anomaly (SAA) to assess the validity of the environmental models at ISS altitudes.

REAS3: A revised implementation of the geosynchrotron model for radio emission from air showers

Over the past years, the freely available Monte Carlo-code REAS which simulates radio emission from air showers based on the geosynchrotron model, was used regularly for comparisons with data. However, it emerged that in the previous version of the code, emission due to the variation of the number of charged particles within an air shower was not taken into account. In the following article, we show the implementation of these emission contributions in REAS3 by the inclusion of “end-point contributions” and discuss the changes on the predictions of REAS obtained by this revision. The basis for describing radiation processes is an universal description which is gained by the use of the end-point formulation. Hence, not only pure geomagnetic radiation is simulated with REAS3 but also radiation due to the variation of the net charge excess in the air shower, independent of the Earth's magnetic field. Furthermore, we present a comparison of lateral distributions of LOPES data with REAS3-simulated distributions. The comparison shows a good agreement between both, data and REAS3 simulations.

Macroscopic geo-magnetic radiation model; polarization effects and finite volume calculations

An ultra-high-energy cosmic ray (UHECR) colliding with the Earth's atmosphere gives rise to an Extensive Air Shower (EAS). Due to different charge separation mechanisms within the thin shower front coherent electromagnetic radiation will be emitted within the radio frequency range. A small deviation of the index of refraction from unity will give rise to Cherenkov radiation up to distances of 100 m from the shower core and therefore has to be included in a complete description of the radio emission from an EAS. Interference between the different radiation mechanisms, in combination with different polarization behavior will reflect in a lateral distribution function (LDF) depending on the orientation of the observer and a non-trivial fall-off of the radio signal as function of distance to the shower core.

Plasma inhomogeneities in the topside ionosphere in the region of the geomagnetic equator and wave radiation according to the APEX satellite data

The measurements of the broadband wave radiation in the topside ionosphere in the region of the geomagnetic equator (the APEX satellite experiment) are presented. The region of unstable plasma with increased density was observed in the nightside topside ionosphere. This region could be formed by heating of the ionosphere from below. An asymmetric distribution of the frequency band width and electrostatic radiation intensity relative to the geomagnetic equator was registered. It has been indicated that a substantial effect of the geomagnetic equator on plasma diffusion from the heating region could be related to the generation, propagation, and damping of electrostatic oscillations and large-scale (as compared to the Larmor ion radius) plasma vortices. The anisotropy in the temperature of the plasma electron component can increase in the regions where the transverse electric field of disturbances damps. The intensity of the electromagnetic radiation, caused by the external sources, apparently, of an artificial origin at frequencies higher than the local plasma frequency, decreases to the radiation detection threshold level in the region of increased plasma density.