Rositsa Miteva - Academia.edu (original) (raw)
Papers by Rositsa Miteva
Publications of the Astronomical Society "Rudjer Boskovic", Dec 1, 2020
Solar gravitational multipolar moments have not been yet extensively analyzed. However, they are ... more Solar gravitational multipolar moments have not been yet extensively analyzed. However, they are at the crossroads of solar physics, solar astrometry, celestial mechanics and General Relativity. Their values reflect the physics of solar models: non-rigid rotation, solar latitudinal rotation, solar-core properties, solar-cycle variations and structure evolution. Their temporal variations are still often neglected; they are yet an essential aspect for constraining solar-cycle modeling or solar-evolution theories. They induced planet-planet inclinations in multitransiting systems gravitating in the neighboring of a star, leading to key issues future studies. This paper is devoted to an analytical analysis; a second part will address an helioseismology analysis.
Proceedings of the SES-2020 conference, Dec 1, 2020
The purpose of this paper is to present an Internet-of-things sensor for ionizing radiation inspe... more The purpose of this paper is to present an Internet-of-things sensor for ionizing radiation inspection of buildings and facilities for ionizing radiation sources and measuring the ionizing radiation dose. A design of a sensor applicable to indoor surveying is presented. The sensor is a lightweight module and is suitable for mobile use either installed on a remotely controlled or autonomous mobile unmanned platform. For test purposes a mobile ground based unmanned vehicle was developed by the authors and the sensor was mounted on that platform. In the case of the utilized testbed, the gamma/beta radiological sensor is directly connected to the main processor unit (digital signal processor microcontroller) of the unmanned platform. The latter was developed to prototype stage and is herein described. The presented novel design is compared to previous work while advantages over existing technology are established. Experimental results of measurements of radiation sources are shown and discussed.
AIP Conference Proceedings, 2019
ABSTRACT Solar energetic particles (SEPs) provide a unique tool to study particle acceleration an... more ABSTRACT Solar energetic particles (SEPs) provide a unique tool to study particle acceleration and propagation in the solar and IP environment. The SEP profiles detected at 1 AU are due to the combined effects of acceleration, injection and transport of these particles. This work is focused towards improving the observational identification of the particle acceleration processes in the solar corona. We re-visit statistical associations between the SEP intensity measured in space and parameters of the parent solar activity, including soft X-rays (peak flux), microwaves (peak flux and fluence), radio spectral parameters and CME speed and width. The work covers all SEPs (electrons and protons to energies of hundreds of MeVs), during the last solar cycle that were associated with flares of X and M class located at western heliolongitudes. In order to assess the IP plasma and field conditions preexisting during the particle propagation, we distinguish two configurations, namely, typical solar wind plasma (and Parker spiral-like magnetic field configuration) and transient magnetic field structures of interplanetary coronal mass ejections (ICMEs). We find that the relationships between the SEP intensity and the parent coronal activity depend on the interplanetary magnetic field configuration, and discuss possible interpretations.
42nd COSPAR Scientific Assembly, Jul 1, 2018
AGU Fall Meeting Abstracts, Dec 1, 2020
EGU General Assembly Conference Abstracts, Apr 1, 2019
International Journal of Aviation, Aeronautics, and Aerospace, 2021
<p><strong>We present a statistical study on the earl... more <p><strong>We present a statistical study on the early evolution of coronal mass ejections (CMEs), to better understand the effect of CME (over)- expansion and how it relates to the production of Solar Energetic Particle (SEP) events. We study the kinematic CME characteristics in terms of their radial and lateral expansion, from their early evolution in the Sun’s atmosphere as observed in EUV imagers and coronagraphs. The data covers 72 CMEs that occurred in the time range of July 2010 to September 2012, where the twin STEREO spacecraft where in quasiquadrature </strong><strong>to the Sun-Earth line. From the STEREO point-of-view, the CMEs under study were observed close to the limb. We calculated the radial and lateral height (width) versus time profiles and derived the corresponding peak and mean velocities, accelerations, and angular expansion rates, with particular emphasis on the role of potential lateral overexpansion in the early CME evolution. We find high correlations between the radial and lateral CME velocities and accelerations. CMEs that are associated tend to be located at the high-value end of the distributions of velocities, widths, and expansion rates compared to nonSEP associated events.<br></strong></p>
Publications of the Astronomical Society "Rudjer Boskovic", Sep 1, 2018
The Catalogues of the solar proton events [Logachev, ed., 1982-2016] provide the homogeneous data... more The Catalogues of the solar proton events [Logachev, ed., 1982-2016] provide the homogeneous data series of events with maximum intensity of > 10 MeV solar protons J ≥ 1 cm-2 s-1 sr-1 beginning from 1970 up to now. The event rates behavior is rather smooth: the total number of such events, relative to accumulated sunspot number, is almost constant in the solar cycles 21-23 and even slightly growing in the solar cycle 24. Contrary, the total number of the most powerful (GLE) events per cycle was constant within statistical errors in the cycles 21-23, and it fell abruptly in cycle 24. Considering the conventional sources of GLEs we found that production of GLEs by X-class bursts was 3 times less in cycle 24 than in cycle 23, while production of GLEs by the >1000 km/s halo-type CMEs was 5 times lower.
EGU General Assembly Conference Abstracts, Apr 1, 2019
EGU General Assembly Conference Abstracts, Apr 1, 2017
The aim of the present report is to outline the observational methods used to determine the solar... more The aim of the present report is to outline the observational methods used to determine the solar origin-in terms of flares and coronal mass ejections (CMEs)-of the in situ observed solar energetic protons. Several widely used guidelines are given and different sources of uncertainties are summarized and discussed. In the present study, a new quality factor is proposed as a certainty check on the so-identified flare-CME pairs. In addition, the correlations between the proton peak intensity and the properties of their solar origin are evaluated as a function of the quality factor.
The Catalogues of the solar proton events [Logachev, ed., 1982-2016] provide the homogeneous data... more The Catalogues of the solar proton events [Logachev, ed., 1982-2016] provide the homogeneous data series of events with maximum intensity of > 10 MeV solar protons J ≥ 1 cm-2 s-1 sr-1 beginning from 1970 up to now. The event rates behavior is rather smooth: the total number of such events, relative to accumulated sunspot number, is almost constant in the solar cycles 21-23 and even slightly growing in the solar cycle 24. Contrary, the total number of the most powerful (GLE) events per cycle was constant within statistical errors in the cycles 21-23, and it fell abruptly in cycle 24. Considering the conventional sources of GLEs we found that production of GLEs by X-class bursts was 3 times less in cycle 24 than in cycle 23, while production of GLEs by the >1000 km/s halo-type CMEs was 5 times lower.
Publications of the Astronomical Society "Rudjer Boskovic", Dec 1, 2020
Solar gravitational multipolar moments have not been yet extensively analyzed. However, they are ... more Solar gravitational multipolar moments have not been yet extensively analyzed. However, they are at the crossroads of solar physics, solar astrometry, celestial mechanics and General Relativity. Their values reflect the physics of solar models: non-rigid rotation, solar latitudinal rotation, solar-core properties, solar-cycle variations and structure evolution. Their temporal variations are still often neglected; they are yet an essential aspect for constraining solar-cycle modeling or solar-evolution theories. They induced planet-planet inclinations in multitransiting systems gravitating in the neighboring of a star, leading to key issues future studies. This paper is devoted to an analytical analysis; a second part will address an helioseismology analysis.
Proceedings of the SES-2020 conference, Dec 1, 2020
The purpose of this paper is to present an Internet-of-things sensor for ionizing radiation inspe... more The purpose of this paper is to present an Internet-of-things sensor for ionizing radiation inspection of buildings and facilities for ionizing radiation sources and measuring the ionizing radiation dose. A design of a sensor applicable to indoor surveying is presented. The sensor is a lightweight module and is suitable for mobile use either installed on a remotely controlled or autonomous mobile unmanned platform. For test purposes a mobile ground based unmanned vehicle was developed by the authors and the sensor was mounted on that platform. In the case of the utilized testbed, the gamma/beta radiological sensor is directly connected to the main processor unit (digital signal processor microcontroller) of the unmanned platform. The latter was developed to prototype stage and is herein described. The presented novel design is compared to previous work while advantages over existing technology are established. Experimental results of measurements of radiation sources are shown and discussed.
AIP Conference Proceedings, 2019
ABSTRACT Solar energetic particles (SEPs) provide a unique tool to study particle acceleration an... more ABSTRACT Solar energetic particles (SEPs) provide a unique tool to study particle acceleration and propagation in the solar and IP environment. The SEP profiles detected at 1 AU are due to the combined effects of acceleration, injection and transport of these particles. This work is focused towards improving the observational identification of the particle acceleration processes in the solar corona. We re-visit statistical associations between the SEP intensity measured in space and parameters of the parent solar activity, including soft X-rays (peak flux), microwaves (peak flux and fluence), radio spectral parameters and CME speed and width. The work covers all SEPs (electrons and protons to energies of hundreds of MeVs), during the last solar cycle that were associated with flares of X and M class located at western heliolongitudes. In order to assess the IP plasma and field conditions preexisting during the particle propagation, we distinguish two configurations, namely, typical solar wind plasma (and Parker spiral-like magnetic field configuration) and transient magnetic field structures of interplanetary coronal mass ejections (ICMEs). We find that the relationships between the SEP intensity and the parent coronal activity depend on the interplanetary magnetic field configuration, and discuss possible interpretations.
42nd COSPAR Scientific Assembly, Jul 1, 2018
AGU Fall Meeting Abstracts, Dec 1, 2020
EGU General Assembly Conference Abstracts, Apr 1, 2019
International Journal of Aviation, Aeronautics, and Aerospace, 2021
<p><strong>We present a statistical study on the earl... more <p><strong>We present a statistical study on the early evolution of coronal mass ejections (CMEs), to better understand the effect of CME (over)- expansion and how it relates to the production of Solar Energetic Particle (SEP) events. We study the kinematic CME characteristics in terms of their radial and lateral expansion, from their early evolution in the Sun’s atmosphere as observed in EUV imagers and coronagraphs. The data covers 72 CMEs that occurred in the time range of July 2010 to September 2012, where the twin STEREO spacecraft where in quasiquadrature </strong><strong>to the Sun-Earth line. From the STEREO point-of-view, the CMEs under study were observed close to the limb. We calculated the radial and lateral height (width) versus time profiles and derived the corresponding peak and mean velocities, accelerations, and angular expansion rates, with particular emphasis on the role of potential lateral overexpansion in the early CME evolution. We find high correlations between the radial and lateral CME velocities and accelerations. CMEs that are associated tend to be located at the high-value end of the distributions of velocities, widths, and expansion rates compared to nonSEP associated events.<br></strong></p>
Publications of the Astronomical Society "Rudjer Boskovic", Sep 1, 2018
The Catalogues of the solar proton events [Logachev, ed., 1982-2016] provide the homogeneous data... more The Catalogues of the solar proton events [Logachev, ed., 1982-2016] provide the homogeneous data series of events with maximum intensity of > 10 MeV solar protons J ≥ 1 cm-2 s-1 sr-1 beginning from 1970 up to now. The event rates behavior is rather smooth: the total number of such events, relative to accumulated sunspot number, is almost constant in the solar cycles 21-23 and even slightly growing in the solar cycle 24. Contrary, the total number of the most powerful (GLE) events per cycle was constant within statistical errors in the cycles 21-23, and it fell abruptly in cycle 24. Considering the conventional sources of GLEs we found that production of GLEs by X-class bursts was 3 times less in cycle 24 than in cycle 23, while production of GLEs by the >1000 km/s halo-type CMEs was 5 times lower.
EGU General Assembly Conference Abstracts, Apr 1, 2019
EGU General Assembly Conference Abstracts, Apr 1, 2017
The aim of the present report is to outline the observational methods used to determine the solar... more The aim of the present report is to outline the observational methods used to determine the solar origin-in terms of flares and coronal mass ejections (CMEs)-of the in situ observed solar energetic protons. Several widely used guidelines are given and different sources of uncertainties are summarized and discussed. In the present study, a new quality factor is proposed as a certainty check on the so-identified flare-CME pairs. In addition, the correlations between the proton peak intensity and the properties of their solar origin are evaluated as a function of the quality factor.
The Catalogues of the solar proton events [Logachev, ed., 1982-2016] provide the homogeneous data... more The Catalogues of the solar proton events [Logachev, ed., 1982-2016] provide the homogeneous data series of events with maximum intensity of > 10 MeV solar protons J ≥ 1 cm-2 s-1 sr-1 beginning from 1970 up to now. The event rates behavior is rather smooth: the total number of such events, relative to accumulated sunspot number, is almost constant in the solar cycles 21-23 and even slightly growing in the solar cycle 24. Contrary, the total number of the most powerful (GLE) events per cycle was constant within statistical errors in the cycles 21-23, and it fell abruptly in cycle 24. Considering the conventional sources of GLEs we found that production of GLEs by X-class bursts was 3 times less in cycle 24 than in cycle 23, while production of GLEs by the >1000 km/s halo-type CMEs was 5 times lower.