scholarly journals Indirect determination of the energy spectra of particles precipitated in the lower ionosphere associated with solar proton events

2000 ◽  
Vol 39 (1) ◽  
pp. 13-19
Author(s):  
Aracy Mendes da Costa
Keyword(s):  
Lower Ionosphere ◽  
Solar Proton ◽  
Energy Spectra ◽  
Indirect Determination ◽  
Solar Proton Events

Los perfiles de densidad electrónica medidos previamente usando la fase y la amplitud de radio señales VLF que se reciben durante los eventos más intensos de protones solares (SPE), junto con el espectro asociado de energías de protones y electrones, los cuales se miden simultáneamente por satélite, nos permiten calcular la razón de producción q(h) de los pares electrón-ion, para las regiones sub-Antártica y Sur Atlántica de la Anomalía Geomagnética (SAGA). Se usaron gráficas de q(h) junto con los perfiles verticales de la densidad electrónica previamente determinados, para calcular el coeficiente efectivo de recombinación ψ(h) para la región SAGA. Asumiendo que los procesos químicos que se llevan a cabo en la baja ionosfera producidos por el impacto de los constituyentes atmosféricos neutrales son básicamente los mismos, se estiman indirectamente los espectros de las partículas energéticas responsables de la ionización detectada con cierto retraso en la región SAGA. Los parámetros que se obtienen coinciden con los resultados presentados por otros muchos autores para el hemisferio norte, además los espectros deducidos están dentro de los límites impuestos por la rigidez magnética y la profundidad de penetración de las partículas incidentes. Los datos experimentales que se presentan en este trabajo corresponden a las señales en VLF transmitidas desde Australia (NWC-22.3 kHz) y Ω-Trinidad (13.6 kHz) y que se recibieron en Atibaia y Curitiba respectivamente, ambas en Brasil, durante el evento de partículas de agosto 4-7, 1972.

Ionization increases associated with the small solar proton events of 5 February 1965 and 16 July 1966

1969 ◽  
Vol 47 (2) ◽  
pp. 131-134 ◽  
Author(s):  
L. W. Hewitt
Keyword(s):  
Lower Ionosphere ◽  
Solar Proton ◽  
Satellite Observations ◽  
Geographic Latitude ◽  
Electron Number ◽  
Partial Reflection ◽  
D Region ◽  
Resolute Bay ◽  
Solar Proton Events

Observations of partial reflections from the ionosphere at vertical incidence at 2.66 MHz have been made at Resolute Bay, geographic latitude 74.7 °N, since September 1963. By measuring the amplitudes of the ordinary and extraordinary backscattered waves information is obtained about electron number densities in the lower ionosphere. The results presented in this paper show that the partial reflection technique is more sensitive than most other ground-based experiments for the detection of D-region ionization increases associated with small solar proton events. Results obtained by the partial reflection experiment during the events of 5 February 1965 and 16 July 1966 are presented and compared with VLF and satellite observations.

Reaction of the high-latitude lower ionosphere to solar proton events from observations in the ELF range

2017 ◽  
Vol 57 (1) ◽  
pp. 51-57 ◽  
Author(s):  
O. M. Lebed’ ◽  
A. V. Larchenko ◽  
S. V. Pil’gaev ◽  
Yu. V. Fedorenko
Keyword(s):  
High Latitude ◽  
Lower Ionosphere ◽  
Solar Proton ◽  
Solar Proton Events

Dynamics of the energy spectra of solar proton events observed in solar cycle 23

2012 ◽  
Vol 46 (3) ◽  
pp. 220-242 ◽  
Author(s):  
I. S. Veselovsky ◽  
I. N. Myagkova ◽  
O. S. Yakovchouk
Keyword(s):  
Solar Cycle ◽  
Solar Proton ◽  
Energy Spectra ◽  
Solar Cycle 23 ◽  
Solar Proton Events

scholarly journals Catalog of Energy Spectra of Solar Proton Events 1970-1979

1970 ◽  
Author(s):  
Galina Bazilevskaya ◽  
◽  
Eduard Vashenyuk ◽  
Vitaly Ishkov ◽  
Leontyi Miroshnichenko ◽  
...  
Keyword(s):  
Solar Proton ◽  
Energy Spectra ◽  
Solar Proton Events

scholarly journals Statistical response of middle atmosphere composition to solar proton events in WACCM-D simulations: importance of lower ionospheric chemistry

2020 ◽  
Author(s):  
Niilo Kalakoski ◽  
Pekka T. Verronen ◽  
Annika Seppälä ◽  
Monika E. Szeląg ◽  
Antti Kero ◽  
...  
Keyword(s):  
Climate Model ◽  
Middle Atmosphere ◽  
Lower Ionosphere ◽  
Solar Proton ◽  
Atmospheric Effects ◽  
Ion Chemistry ◽  
Global Models ◽  
Superposed Epoch Analysis ◽  
D Region ◽  
Solar Proton Events

Abstract. Atmospheric effects of solar proton events (SPE) have been studied for decades, because their drastic impact can be used to test our understanding of upper stratospheric and mesospheric chemistry in the polar cap regions. For example, SPEs cause production of odd hydrogen and odd nitrogen, which leads to depletion of ozone in catalytic reactions, such that the effects are easily observed from satellites during the largest events. Until recently, the complexity of the ion chemistry in the lower ionosphere (i.e. in the D region) has restricted global models to simplified parameterizations of chemical impacts induced by energetic particle precipitation (EPP). Because of this restriction, global models have been unable to correctly reproduce some important effects, such as the increase of mesospheric HNO3 or the changes in chlorine species. Here we use simulations from the WACCM-D model, a variant of the Whole Atmosphere Community Climate Model, to study the statistical response of the atmosphere to the 66 largest SPEs that occurred in years 1989–2012. Our model includes a set of D-region ion chemistry, designed for a detailed representation of the atmospheric effects of SPEs and EPP in general. We use superposed epoch analysis to study changes in O3, HOx (OH + HO2), Clx (Cl + ClO), HNO3, NOx (NO + NO2) and H2O. Compared to the standard WACCM which uses an ion chemistry parameterization, WACCM-D produces a larger response in O3 and NOx, weaker response in HOx and introduces changes in HNO3 and Clx. These differences between WACCM and WACCM-D highlight the importance of including ion chemistry reactions in models used to study EPP.

scholarly journals Statistical response of middle atmosphere composition to solar proton events in WACCM-D simulations: the importance of lower ionospheric chemistry

2021 ◽  
Author(s):  
Niilo Kalakoski ◽  
Pekka T. Verronen ◽  
Annika Seppälä ◽  
Monika E. Szeląg ◽  
Antti Kero ◽  
...  
Keyword(s):  
Climate Model ◽  
Middle Atmosphere ◽  
Lower Ionosphere ◽  
Solar Proton ◽  
Atmospheric Effects ◽  
Ion Chemistry ◽  
Global Models ◽  
Superposed Epoch Analysis ◽  
D Region ◽  
Solar Proton Events

<p>Atmospheric effects of solar proton events (SPEs) have been studied for decades, because their drastic impact can be used to test our understanding of upper stratospheric and mesospheric chemistry in the polar cap regions. For example, odd hydrogen and odd nitrogen are produced during SPEs, which leads to depletion of ozone in catalytic reactions, such that the effects are easily observed from satellites during the strongest events. Until recently, the complexity of the ion chemistry in the lower ionosphere (i.e., in the D region) has restricted global models to simplified parameterizations of chemical impacts induced by energetic particle precipitation (EPP). Because of this restriction, global models have been unable to correctly reproduce some important effects, such as the increase in mesospheric HNO<sub>3</sub> or the changes in chlorine species. Here we use simulations from the WACCM-D model, a variant of the Whole Atmosphere Community Climate Model, to study the statistical response of the atmosphere to the 66 strongest SPEs which occurred in the years 1989–2012. Our model includes a set of D-region ion chemistry, designed for a detailed representation of the atmospheric effects of SPEs and EPP in general. We use superposed epoch analysis to study changes in O<sub>3</sub>, HO<sub>x</sub> (OH + HO<sub>2</sub>), Cl<sub>x</sub> (Cl + ClO), HNO<sub>3</sub>, NO<sub>x</sub> (NO + NO<sub>2</sub>) and H<sub>2</sub>O. Compared to the standard WACCM which uses an ion chemistry parameterization, WACCM-D produces a larger response in O<sub>3</sub> and NO<sub>x</sub> and a weaker response in HO<sub>x</sub> and introduces changes in HNO<sub>3</sub> and Cl<sub>x</sub>. These differences between WACCM and WACCM-D highlight the importance of including ion chemistry reactions in models used to study EPP. </p>

scholarly journals Statistical response of middle atmosphere composition to solar proton events in WACCM-D simulations: the importance of lower ionospheric chemistry

2020 ◽  
Vol 20 (14) ◽  
pp. 8923-8938 ◽  
Author(s):  
Niilo Kalakoski ◽  
Pekka T. Verronen ◽  
Annika Seppälä ◽  
Monika E. Szeląg ◽  
Antti Kero ◽  
...  
Keyword(s):  
Climate Model ◽  
Middle Atmosphere ◽  
Lower Ionosphere ◽  
Solar Proton ◽  
Atmospheric Effects ◽  
Ion Chemistry ◽  
Global Models ◽  
Superposed Epoch Analysis ◽  
D Region ◽  
Solar Proton Events

Abstract. Atmospheric effects of solar proton events (SPEs) have been studied for decades, because their drastic impact can be used to test our understanding of upper stratospheric and mesospheric chemistry in the polar cap regions. For example, odd hydrogen and odd nitrogen are produced during SPEs, which leads to depletion of ozone in catalytic reactions, such that the effects are easily observed from satellites during the strongest events. Until recently, the complexity of the ion chemistry in the lower ionosphere (i.e., in the D region) has restricted global models to simplified parameterizations of chemical impacts induced by energetic particle precipitation (EPP). Because of this restriction, global models have been unable to correctly reproduce some important effects, such as the increase in mesospheric HNO3 or the changes in chlorine species. Here we use simulations from the WACCM-D model, a variant of the Whole Atmosphere Community Climate Model, to study the statistical response of the atmosphere to the 66 strongest SPEs which occurred in the years 1989–2012. Our model includes a set of D-region ion chemistry, designed for a detailed representation of the atmospheric effects of SPEs and EPP in general. We use superposed epoch analysis to study changes in O3, HOx (OH + HO2), Clx (Cl + ClO), HNO3, NOx (NO + NO2) and H2O. Compared to the standard WACCM which uses an ion chemistry parameterization, WACCM-D produces a larger response in O3 and NOx and a weaker response in HOx and introduces changes in HNO3 and Clx. These differences between WACCM and WACCM-D highlight the importance of including ion chemistry reactions in models used to study EPP.

Indirect Determination of Amikacin by Gold Nanoparticles as Redox Probe

2020 ◽  
Vol 17 ◽  
Author(s):  
Mansureh Alizadeh ◽  
Mandana Amiri ◽  
Abolfazl Bezaatpour
Keyword(s):  
Gold Nanoparticles ◽  
Bacterial Infections ◽  
Limit Of Detection ◽  
Pharmaceutical Preparation ◽  
Cathodic Peak ◽  
Easy Method ◽  
Peak Current ◽  
Indirect Determination ◽  
Tract Infections

: Amikacin is an aminoglycoside antibiotic used for many gram-negative bacterial infections like infections in the urinary tract, infections in brain, lungs and abdomen. Electrochemical determination of amikacin is a challenge in electroanalysis because it shows no voltammetric peak at the surface of bare electrodes. In this approach, a very simple and easy method for indirect voltammetric determination of amikacin presented in real samples. Gold nanoparticles were electrodeposited at the surface of glassy carbon electrode in constant potential. The effect of several parameters such as time and potential of deposition, pH and scan rates on signal were studied. The cathodic peak current of Au3+ decreased with increasing amikacin concentration. Quantitative analysis of amikacin was performed using differential pulse voltammetry by following cathodic peak current of gold ions. Two dynamic linear ranges of 1.0 × 10−8–1.0 × 10-7 M and 5.0 × 10−7–1.0 × 10-3 M were obtained and limit of detection was estimated 3.0× 10−9 M. The method was successfully determined amikacin in pharmaceutical preparation and human serum. The effect of several interference in determination of amikacin was also studied.

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