Peter Velinov - Academia.edu (original) (raw)

Papers by Peter Velinov

Dokladi na Bʺlgarskata akademiâ na naukite, Jan 30, 2023

Aerospace Research in Bulgaria, 2024

Proceedings of 27th European Cosmic Ray Symposium — PoS(ECRS)

This investigation is based on a new model CORSIMA (COsmic Ray Spectra and Intensity in Middle At... more This investigation is based on a new model CORSIMA (COsmic Ray Spectra and Intensity in Middle Atmosphere). Numerical simulations of Galactic Cosmic Ray (GCR) spectra and intensity for the middle atmosphere and lower altitudes of the ionosphere (30-80 km) are presented. These altitudes are above the Regener-Pfotzer maximum. The full GCR composition (protons p, alpha particles , and heavier nuclei groups: light L, medium M, heavy H, very heavy VH) is used [1]. Analytical expressions for the energy interval contributions are provided. An approximation of the ionization function on six energy intervals is used and the charge decrease interval for electron capture is studied. The development of this research is important for a better understanding of the processes and mechanisms of space physics and space weather. GCR have an impact on the ionization and electrical parameters in the atmosphere and also on the chemical processes (ozone formation and depletion in the stratosphere) in it. These effects can be significantly enhanced during strong and moderately strong solar energetic particle events and geomagnetic storms.

High-energy precipitating particles of cosmic origin viz. cosmic ray (CR) protons of heavier nucl... more High-energy precipitating particles of cosmic origin viz. cosmic ray (CR) protons of heavier nuclei of galactic and/or solar origin induce complicated nuclear-electromagnetic-lepton cascades in the Earth's atmosphere, eventually leading to an ionization of the ambient air. The induced by CRs ionization is related to possible effect of precipitating particles on physico-chemical processes in the atmosphere. These effects can be considerably enhanced during solar proton events. While the contribution of galactic CRs to ion production in the atmosphere is slightly variable throughout a solar cycle, relativistic solar particles could produce a significant excess of electron-ion pair production, particularly over polar caps. This effect is strong on short time scales. On the other hand, depressions of the galactic CR flux, that is, Forbush decreases, can significantly impact on induced ionization. The sequence of three ground level enhancements (GLEs) 65, 66 and 67 in October-November 2003, specifically GLE 66 occurred during a giant Forbush decrease, provides unique opportunity to study impact ionization on enhanced manner and extended time scale, explicitly considering the reduced galactic CR flux. Using Monte Carlo simulations and appropriate solar proton spectra we computed the ion production rate and the corresponding ionization effect in the Earth atmosphere during GLE 66 which occurred on

Proceedings of the Bulgarian Academy of Sciences

The influence of Anomalous Cosmic Rays (ACRs) on ionization in the boundary of the ionosphere-mid... more The influence of Anomalous Cosmic Rays (ACRs) on ionization in the boundary of the ionosphere-middle atmosphere system (40–50 km) is investigated, taking into account the spectrum, intensity, geomagnetic, and atmospheric cut-offs. The ACR spectra and intensity in the middle atmosphere are determined using the CORSIMA (COsmic Ray Spectra and Intensity in Middle Atmosphere) model. ACR spectra are presented for various atmospheric altitudes within the range of 40–50 km, with the lower boundary of the ionosphere at approximately 50 km. Experimental satellite measurements are utilized for the main ACR constituents, including Hydrogen (protons), Helium, Nitrogen, and Oxygen nuclei. It is found that the influence of ACRs extends to the polar cap regions above 65°–70° geomagnetic latitude, and certain ACR ionization rate values in these regions are comparable to Galactic Cosmic Ray (GCR) ionization rates. Future studies will also consider Multiply Charged Anomalous Cosmic Rays (MCACRs), whi...

Abstract: We propose models which generalize the differential D(E) spectra of galactic (GCR) and ... more Abstract: We propose models which generalize the differential D(E) spectra of galactic (GCR) and anomalous cosmic rays (ACR) during the 11-year solar cycle. The models take into account the cos-mic ray (CR) modulation in the Heliosphere. We describe the connection between solar activity varia-tion and the values of model parameters. Our analyses show that the contribution of GCRs and ACRs to the ionization of the ionospheres of outer planets (Jupiter, Saturn, Uranus, Neptune) will increase with growth of the planetary distances from the Sun. The modulated energy spectra of galactic cosmic rays are compared with force field approximation for protons and alpha particles. The error is in the order of 1.5%. The model solutions are compared with IMAX92, CAPRICE94 and AMS98 measure-ments. The proposed analytical models give practical possibility for investigation of experimental data from measurements of galactic cosmic rays and their anomalous component. 1.

One of the main drivers of the possible effect of cosmic ray particles on atmospheric physics and... more One of the main drivers of the possible effect of cosmic ray particles on atmospheric physics and chemistry is connected to the Induced Atmospheric Ionization (IAI) due to high-energy precipitating particles. IAI by cosmic rays, which can be considerably enhanced during solar proton events, was extensively discussed over the last decade. In most of the recent models, IAI plays a key role on the physics and chemistry of the atmosphere, specifically on minor constituents. It is known that the contribution of galactic cosmic ray particles to ion production in the atmosphere is nearly constant, slightly influenced by the solar activity. On the other hand, the relativistic solar particles could produce a significant excess of ion pair production, particularly over polar caps. This effect is normally strong at short time scales. The sequence of three ground level enhancements GLE 65, 66 & 67 in October-November 2003 gives an unique opportunity to study impact ionization on enhanced manner and extended time scale. Using Monte Carlo simulation and derived solar proton spectra, we computed the ion production and the corresponding ionization effect in the Earth atmosphere in the region of Regener-Pfotzer maximum during the so-called Halloween events in October-November 2003.

Journal of Atmospheric and Solar-Terrestrial Physics, 2016

Abstract Thunderstorms play significant role in the upward electrical coupling between the tropos... more Abstract Thunderstorms play significant role in the upward electrical coupling between the troposphere and lower ionosphere by quasi-static (QS) electric fields generated by quiet conditions (by slow variations of electric charges), as well as during lightning discharges when they can be strong enough to produce in the nighttime lower ionosphere sprites. Changes are caused in lower ionosphere by the QS electric fields before a sprite-producing lightning discharge which can play role in formation of the stronger sprite-driving transient QS electric fields due to lightning. These changes include electron heating, modifications of conductivity and electron density, etc. We demonstrate that such changes depend on the geomagnetic latitude determining the magnetic field lines inclination, and thus, the anisotropic conductivity. Our previous results show that the QS electric fields in the lower ionosphere above equatorial thunderstorms are much bigger and have larger horizontal extension than those generated at high and middle altitudes by otherwise same conditions. Now we estimate by modeling the electric currents and fields generated in lower ionosphere above equatorial thunderstorms of different horizontal dimensions during quiet periods and of their self-consistent effects to conductivity whose modifications can play role in formation of post-lightning sprite-producing electric fields. Specific electric currents configurations and distributions of related electric fields are estimated first by ambient conductivity. Then, these are evaluated self-consistently with conductivity modification. The electric currents are re-oriented above ~85 km and flow in a narrow horizontal layer where they dense. Respectively, the electric fields and their effect on conductivity have much larger horizontal scale than at middle latitudes (few hundred of kilometers). Horizontally large sources, such as mesoscale convective structures, cause enhancements of electric fields and their effects. These modified features may affect production of sprites.

Proceedings of the Bulgarian Academy of Sciences

High-energy precipitating particles of cosmic origin viz. cosmic ray protons of heavier nuclei of... more High-energy precipitating particles of cosmic origin viz. cosmic ray protons of heavier nuclei of galactic and/or solar origin induce complicated nuclear electromagnetic-lepton cascades in the Earth’s atmosphere, eventually leading to an ionization of the ambient air. The induced by cosmic rays atmospheric ionization is related to possible effect of precipitating particles on atmospheric chemistry and physics. In this work, using a combination of state of the art 3-D full target models we computed as realistically as possible, explicitly considering the contribution of heavy ions, the ion production at eight altitudes in the Earth’s atmosphere, scilicet: 25 g/cm2 (≈ 45 km asl), 50 g/cm2 (≈ 35 km asl) Fig. 1, 100 g/cm2 (≈ 24.5 km asl), 150 g/cm2 (≈ 19.5 km asl) Fig. 2, 200 g/cm2 (≈ 16 km asl), 250 g/cm2 (≈ 13.5 km asl) Fig. 3, 300 g/cm2 (≈ 11.5 km asl), 400 g/cm2 (≈ 8.5 km asl) Fig. 4. This includes altitudes from the upper troposphere to the stratosphere. Here we provided glob...

Aerospace Research in Bulgaria, 2021

On April 12, 1961, Yuri Gagarin proclaimed the arrival of a new space age. The rapid advances in ... more On April 12, 1961, Yuri Gagarin proclaimed the arrival of a new space age. The rapid advances in the different space sciences and technologies began after the first human spaceflight. Then fundamentally new sciences and technologies appeared. At present, space science covers a broad range of disciplines. The following outline is provided as an overview and topical guide to space sciences: Astronomy and Space Astronomy, Cosmology, Astrophysics, Space Physics, Solar-Terrestrial Physics, Aeronomy, Solar physics, Heliospheric Physics, Cosmic Ray Physics, Space Weather and Space Climate (Earth-Space Climatology), Space Dosimetry, Space Chemistry or Cosmochemistry, Remote Sensing of the Earth and Planets, Planetary Science, Planetary Geology, Astrogeology or Exogeology, Exoplanetology or Exoplanetary Science (Science for Extrasolar Planetary Systems), Intelligent Life in the Universe, Astronautics (or Cosmonautics), Orbital mechanics or Astrodynamics, Space life sciences: Bioastronautics,...

Proceedings of 36th International Cosmic Ray Conference — PoS(ICRC2019), 2019

Galactic cosmic rays are the main source of ionization in the Earth's stratosphere and tropo-* Sp... more Galactic cosmic rays are the main source of ionization in the Earth's stratosphere and tropo-* Speaker.

An important topic in the field of solar-terrestrial and space physics is the highly discussed po... more An important topic in the field of solar-terrestrial and space physics is the highly discussed possible effect of cosmic ray (CR) particles on atmospheric chemistry and physics, specifically by induced ionization. In most of the recently developed models, the induced by CRs atmospheric ionization plays a significant role. Nowadays, it is clear that the contribution of galactic cosmic ray particles to electron-ion production in the atmosphere slightly varies with the solar modulation and transient effects. On the other hand, high energy solar particles could produce complicated hadron-electromagnetic-muon cascade in the atmosphere of the Earth and significantly enhance the electron-ion pair production, particularly over polar caps. This effect is usually strong on a short time scales, being more important in the region of Regener-Pfotzer maximum. However, for some atmospheric chemistry and physics purposes it is important to estimate the ionization effect in the middle stratosphere. The Ground Level Enhancement GLE 59 on Bastille Day 14 of July 2000 and the maverick GLE 70 on 13 December 2006 are among the strongest recorded events during the previous solar cycle 23. Herein, using recently proposed full target Monte Carlo simulation and previously derived high energy solar particles energy spectra we estimated the electron-ion production rate and corresponding ionization effect in the Earth middle stratosphere during two moderately strong ground level enhancement events.

Proceeding of the Bulgarian Academy of Sciences, 2013

In this work we investigate the effects of solar cosmic ray (SCR) from the GLE (Ground Level Enha... more In this work we investigate the effects of solar cosmic ray (SCR) from the GLE (Ground Level Enhancement) 69 on 20 January 2005 and GLE 05 on 23 February 1956. For this purpose we apply our operational programme CORIMIA (COsmic Ray Ionization Model for Ionosphere and Atmosphere). In the final version of the applied model an approximation in 5 characteristic energy intervals of the Bohr-Bethe-Bethe function including charge decrease interval is used. For the first time we present these quantitative and qualitative appreciations of the SCR fluxes impact from these Solar Particle Events (SPE) on the ionosphere and middle atmosphere (30-120 km). Unlike the cases of galactic cosmic rays (GCR), SCR differential spectra vary essentially in time during the course of the investigated event. Also SCR fluxes differ from one another for different events. The profiles behaviour is explained taking into account the structure of the CORIMIA programme. The computational results are in accordance with the experimental data. They show characteristic features of the ionization rate process for different geomagnetic latitudes and altitudes. The calculations are performed over geomagnetic latitudes 65 •-90 • as the profiles values grow strongly at high latitudes.

Dokladi na Bʺlgarskata akademiâ na naukite, Jan 30, 2023

Aerospace Research in Bulgaria, 2024

Proceedings of 27th European Cosmic Ray Symposium — PoS(ECRS)

This investigation is based on a new model CORSIMA (COsmic Ray Spectra and Intensity in Middle At... more This investigation is based on a new model CORSIMA (COsmic Ray Spectra and Intensity in Middle Atmosphere). Numerical simulations of Galactic Cosmic Ray (GCR) spectra and intensity for the middle atmosphere and lower altitudes of the ionosphere (30-80 km) are presented. These altitudes are above the Regener-Pfotzer maximum. The full GCR composition (protons p, alpha particles , and heavier nuclei groups: light L, medium M, heavy H, very heavy VH) is used [1]. Analytical expressions for the energy interval contributions are provided. An approximation of the ionization function on six energy intervals is used and the charge decrease interval for electron capture is studied. The development of this research is important for a better understanding of the processes and mechanisms of space physics and space weather. GCR have an impact on the ionization and electrical parameters in the atmosphere and also on the chemical processes (ozone formation and depletion in the stratosphere) in it. These effects can be significantly enhanced during strong and moderately strong solar energetic particle events and geomagnetic storms.

High-energy precipitating particles of cosmic origin viz. cosmic ray (CR) protons of heavier nucl... more High-energy precipitating particles of cosmic origin viz. cosmic ray (CR) protons of heavier nuclei of galactic and/or solar origin induce complicated nuclear-electromagnetic-lepton cascades in the Earth's atmosphere, eventually leading to an ionization of the ambient air. The induced by CRs ionization is related to possible effect of precipitating particles on physico-chemical processes in the atmosphere. These effects can be considerably enhanced during solar proton events. While the contribution of galactic CRs to ion production in the atmosphere is slightly variable throughout a solar cycle, relativistic solar particles could produce a significant excess of electron-ion pair production, particularly over polar caps. This effect is strong on short time scales. On the other hand, depressions of the galactic CR flux, that is, Forbush decreases, can significantly impact on induced ionization. The sequence of three ground level enhancements (GLEs) 65, 66 and 67 in October-November 2003, specifically GLE 66 occurred during a giant Forbush decrease, provides unique opportunity to study impact ionization on enhanced manner and extended time scale, explicitly considering the reduced galactic CR flux. Using Monte Carlo simulations and appropriate solar proton spectra we computed the ion production rate and the corresponding ionization effect in the Earth atmosphere during GLE 66 which occurred on

Proceedings of the Bulgarian Academy of Sciences

The influence of Anomalous Cosmic Rays (ACRs) on ionization in the boundary of the ionosphere-mid... more The influence of Anomalous Cosmic Rays (ACRs) on ionization in the boundary of the ionosphere-middle atmosphere system (40–50 km) is investigated, taking into account the spectrum, intensity, geomagnetic, and atmospheric cut-offs. The ACR spectra and intensity in the middle atmosphere are determined using the CORSIMA (COsmic Ray Spectra and Intensity in Middle Atmosphere) model. ACR spectra are presented for various atmospheric altitudes within the range of 40–50 km, with the lower boundary of the ionosphere at approximately 50 km. Experimental satellite measurements are utilized for the main ACR constituents, including Hydrogen (protons), Helium, Nitrogen, and Oxygen nuclei. It is found that the influence of ACRs extends to the polar cap regions above 65°–70° geomagnetic latitude, and certain ACR ionization rate values in these regions are comparable to Galactic Cosmic Ray (GCR) ionization rates. Future studies will also consider Multiply Charged Anomalous Cosmic Rays (MCACRs), whi...

Abstract: We propose models which generalize the differential D(E) spectra of galactic (GCR) and ... more Abstract: We propose models which generalize the differential D(E) spectra of galactic (GCR) and anomalous cosmic rays (ACR) during the 11-year solar cycle. The models take into account the cos-mic ray (CR) modulation in the Heliosphere. We describe the connection between solar activity varia-tion and the values of model parameters. Our analyses show that the contribution of GCRs and ACRs to the ionization of the ionospheres of outer planets (Jupiter, Saturn, Uranus, Neptune) will increase with growth of the planetary distances from the Sun. The modulated energy spectra of galactic cosmic rays are compared with force field approximation for protons and alpha particles. The error is in the order of 1.5%. The model solutions are compared with IMAX92, CAPRICE94 and AMS98 measure-ments. The proposed analytical models give practical possibility for investigation of experimental data from measurements of galactic cosmic rays and their anomalous component. 1.

One of the main drivers of the possible effect of cosmic ray particles on atmospheric physics and... more One of the main drivers of the possible effect of cosmic ray particles on atmospheric physics and chemistry is connected to the Induced Atmospheric Ionization (IAI) due to high-energy precipitating particles. IAI by cosmic rays, which can be considerably enhanced during solar proton events, was extensively discussed over the last decade. In most of the recent models, IAI plays a key role on the physics and chemistry of the atmosphere, specifically on minor constituents. It is known that the contribution of galactic cosmic ray particles to ion production in the atmosphere is nearly constant, slightly influenced by the solar activity. On the other hand, the relativistic solar particles could produce a significant excess of ion pair production, particularly over polar caps. This effect is normally strong at short time scales. The sequence of three ground level enhancements GLE 65, 66 & 67 in October-November 2003 gives an unique opportunity to study impact ionization on enhanced manner and extended time scale. Using Monte Carlo simulation and derived solar proton spectra, we computed the ion production and the corresponding ionization effect in the Earth atmosphere in the region of Regener-Pfotzer maximum during the so-called Halloween events in October-November 2003.

Journal of Atmospheric and Solar-Terrestrial Physics, 2016

Abstract Thunderstorms play significant role in the upward electrical coupling between the tropos... more Abstract Thunderstorms play significant role in the upward electrical coupling between the troposphere and lower ionosphere by quasi-static (QS) electric fields generated by quiet conditions (by slow variations of electric charges), as well as during lightning discharges when they can be strong enough to produce in the nighttime lower ionosphere sprites. Changes are caused in lower ionosphere by the QS electric fields before a sprite-producing lightning discharge which can play role in formation of the stronger sprite-driving transient QS electric fields due to lightning. These changes include electron heating, modifications of conductivity and electron density, etc. We demonstrate that such changes depend on the geomagnetic latitude determining the magnetic field lines inclination, and thus, the anisotropic conductivity. Our previous results show that the QS electric fields in the lower ionosphere above equatorial thunderstorms are much bigger and have larger horizontal extension than those generated at high and middle altitudes by otherwise same conditions. Now we estimate by modeling the electric currents and fields generated in lower ionosphere above equatorial thunderstorms of different horizontal dimensions during quiet periods and of their self-consistent effects to conductivity whose modifications can play role in formation of post-lightning sprite-producing electric fields. Specific electric currents configurations and distributions of related electric fields are estimated first by ambient conductivity. Then, these are evaluated self-consistently with conductivity modification. The electric currents are re-oriented above ~85 km and flow in a narrow horizontal layer where they dense. Respectively, the electric fields and their effect on conductivity have much larger horizontal scale than at middle latitudes (few hundred of kilometers). Horizontally large sources, such as mesoscale convective structures, cause enhancements of electric fields and their effects. These modified features may affect production of sprites.

Proceedings of the Bulgarian Academy of Sciences

High-energy precipitating particles of cosmic origin viz. cosmic ray protons of heavier nuclei of... more High-energy precipitating particles of cosmic origin viz. cosmic ray protons of heavier nuclei of galactic and/or solar origin induce complicated nuclear electromagnetic-lepton cascades in the Earth’s atmosphere, eventually leading to an ionization of the ambient air. The induced by cosmic rays atmospheric ionization is related to possible effect of precipitating particles on atmospheric chemistry and physics. In this work, using a combination of state of the art 3-D full target models we computed as realistically as possible, explicitly considering the contribution of heavy ions, the ion production at eight altitudes in the Earth’s atmosphere, scilicet: 25 g/cm2 (≈ 45 km asl), 50 g/cm2 (≈ 35 km asl) Fig. 1, 100 g/cm2 (≈ 24.5 km asl), 150 g/cm2 (≈ 19.5 km asl) Fig. 2, 200 g/cm2 (≈ 16 km asl), 250 g/cm2 (≈ 13.5 km asl) Fig. 3, 300 g/cm2 (≈ 11.5 km asl), 400 g/cm2 (≈ 8.5 km asl) Fig. 4. This includes altitudes from the upper troposphere to the stratosphere. Here we provided glob...

Aerospace Research in Bulgaria, 2021

On April 12, 1961, Yuri Gagarin proclaimed the arrival of a new space age. The rapid advances in ... more On April 12, 1961, Yuri Gagarin proclaimed the arrival of a new space age. The rapid advances in the different space sciences and technologies began after the first human spaceflight. Then fundamentally new sciences and technologies appeared. At present, space science covers a broad range of disciplines. The following outline is provided as an overview and topical guide to space sciences: Astronomy and Space Astronomy, Cosmology, Astrophysics, Space Physics, Solar-Terrestrial Physics, Aeronomy, Solar physics, Heliospheric Physics, Cosmic Ray Physics, Space Weather and Space Climate (Earth-Space Climatology), Space Dosimetry, Space Chemistry or Cosmochemistry, Remote Sensing of the Earth and Planets, Planetary Science, Planetary Geology, Astrogeology or Exogeology, Exoplanetology or Exoplanetary Science (Science for Extrasolar Planetary Systems), Intelligent Life in the Universe, Astronautics (or Cosmonautics), Orbital mechanics or Astrodynamics, Space life sciences: Bioastronautics,...

Proceedings of 36th International Cosmic Ray Conference — PoS(ICRC2019), 2019

Galactic cosmic rays are the main source of ionization in the Earth's stratosphere and tropo-* Sp... more Galactic cosmic rays are the main source of ionization in the Earth's stratosphere and tropo-* Speaker.

An important topic in the field of solar-terrestrial and space physics is the highly discussed po... more An important topic in the field of solar-terrestrial and space physics is the highly discussed possible effect of cosmic ray (CR) particles on atmospheric chemistry and physics, specifically by induced ionization. In most of the recently developed models, the induced by CRs atmospheric ionization plays a significant role. Nowadays, it is clear that the contribution of galactic cosmic ray particles to electron-ion production in the atmosphere slightly varies with the solar modulation and transient effects. On the other hand, high energy solar particles could produce complicated hadron-electromagnetic-muon cascade in the atmosphere of the Earth and significantly enhance the electron-ion pair production, particularly over polar caps. This effect is usually strong on a short time scales, being more important in the region of Regener-Pfotzer maximum. However, for some atmospheric chemistry and physics purposes it is important to estimate the ionization effect in the middle stratosphere. The Ground Level Enhancement GLE 59 on Bastille Day 14 of July 2000 and the maverick GLE 70 on 13 December 2006 are among the strongest recorded events during the previous solar cycle 23. Herein, using recently proposed full target Monte Carlo simulation and previously derived high energy solar particles energy spectra we estimated the electron-ion production rate and corresponding ionization effect in the Earth middle stratosphere during two moderately strong ground level enhancement events.

Proceeding of the Bulgarian Academy of Sciences, 2013

In this work we investigate the effects of solar cosmic ray (SCR) from the GLE (Ground Level Enha... more In this work we investigate the effects of solar cosmic ray (SCR) from the GLE (Ground Level Enhancement) 69 on 20 January 2005 and GLE 05 on 23 February 1956. For this purpose we apply our operational programme CORIMIA (COsmic Ray Ionization Model for Ionosphere and Atmosphere). In the final version of the applied model an approximation in 5 characteristic energy intervals of the Bohr-Bethe-Bethe function including charge decrease interval is used. For the first time we present these quantitative and qualitative appreciations of the SCR fluxes impact from these Solar Particle Events (SPE) on the ionosphere and middle atmosphere (30-120 km). Unlike the cases of galactic cosmic rays (GCR), SCR differential spectra vary essentially in time during the course of the investigated event. Also SCR fluxes differ from one another for different events. The profiles behaviour is explained taking into account the structure of the CORIMIA programme. The computational results are in accordance with the experimental data. They show characteristic features of the ionization rate process for different geomagnetic latitudes and altitudes. The calculations are performed over geomagnetic latitudes 65 •-90 • as the profiles values grow strongly at high latitudes.