We present simulations of the terrestrial and Martian paleo-magnetosphere for ~4.1-4.0 billion ye... more We present simulations of the terrestrial and Martian paleo-magnetosphere for ~4.1-4.0 billion years (Gyr) ago, which were performed with adapted versions of the Paraboloid Magnetospheric Model (PMM) of the Skobeltsyn Institute for Nuclear Physics of the Moscow State University. For the Earth our simulations show that the paleo-magnetosphere was significantly smaller than today, with a standoffdistance rs ranging from ~3.4 to ~8.2 Re, depending on the chosen input parameters. Our simulations also show that the Martian paleo-magnetosphere should have been comparable in size to the terrestrial paleomagnetosphere until its cessation ~4.0 Gyr ago. At Earth, a nitrogen-dominated atmosphere would not have survived the harsh conditions during the late Hadean eon, i.e. ~4.1 Gyr ago, whereas a CO2dominated atmosphere could have survived. Further implications for the ancient atmospheres of Earth and Mars will be discussed.
Journal of Geophysical Research: Space Physics, 2015
We investigate the magnetic perturbations associated with field‐aligned currents observed on 34 C... more We investigate the magnetic perturbations associated with field‐aligned currents observed on 34 Cassini passes over the premidnight northern auroral region during 2008. These are found to be significantly modulated not only by the northern planetary‐period oscillation (PPO) system, similar to the southern currents by the southern PPO system found previously, but also by the southern PPO system as well, thus providing the first clear evidence of PPO‐related interhemispheric current flow. The principal field‐aligned currents of the two PPO systems are found to be co‐located in northern ionospheric colatitude, together with the currents of the PPO‐independent (subcorotation) system, located between the vicinity of the open‐closed field boundary and field lines mapping to ~9 Saturn radius (Rs) in the equatorial plane. All three systems are of comparable magnitude, ~3 MA in each PPO half‐cycle. Smaller PPO‐related field‐aligned currents of opposite polarity also flow in the interior regi...
Journal of Geophysical Research: Space Physics, 2015
A thin current sheet (TCS), with the width of an order of thermal proton gyroradius, appears a fu... more A thin current sheet (TCS), with the width of an order of thermal proton gyroradius, appears a fundamental physical object which plays an important role in structuring of major magnetospheric current systems (magnetotail, magnetodisk, etc.). The TCSs are nowadays under extensive study by means of space missions and theoretical models. We consider a simple model of the TCS separating two half‐spaces occupied by a homogenous magnetic field of opposite sign tangential to the TCS; a small normal component of the magnetic field is prescribed. An analytical solution for the electric current and plasma density in the close vicinity of the TCS has been obtained and compared with numerical simulation. The number density and the electric current profiles have two maxima each. The characteristic spatial scale zS of the maxima location was investigated as a function of initial pitch angle of an incoming charge particle. The effect of the thermal dispersion of the incoming proton beam have been ...
First we discuss the solar wind plasma interaction with the Solar System planets that have intrin... more First we discuss the solar wind plasma interaction with the Solar System planets that have intrinsic magnetic fields : Mercury , Earth , Jupiter , and Saturn are discussed. As a result of such an interaction cavities, which are free from the solar wind plasma and occupied by the planetary magnetic field are created. These cavities are usually called magnetospheres are surrounded and bound by the magnetopause . The magnetopause preserved the planetary magnetic field penetration into the magnetosheath so that its impossible for the magnetosheath plasma flow to penetrate into the magnetosphere. The magnetosheath are placed between the bow shock and the magnetopause. The bow shock forms a boundary against the unshocked super Alvenic plasma flow. As demonstrated by the analysis of the Mercury, Earth, Jupiter, and Saturn magnetopauses, these surfaces can be well described by a paraboloid of revolution with different subsolar distances and flaring angles. Based on this fact an universal model of the planetary magnetosphere can be constructed. We chose the planets in the inner magnetospheres of which the magnetic field vectors have been measured by orbiting spacecraft magnetometers. The proposed models describe the basic physical processes that are responsible for the structure and dynamics of the planetary magnetospheres . Additionally to the inner planetary field the different magnetospheric sources of magnetic field are included in the model. Finally, we discuss how these magnetosphere models can be applied to exoplanets in a comparative way.
Journal of Geophysical Research: Space Physics, 2008
A new “Paraboloidal” model of Mercury's magnetospheric magnetic fiel... more A new “Paraboloidal” model of Mercury's magnetospheric magnetic field based upon the earlier terrestrial model and using similar techniques is developed. The model describes the field of Mercury's dipole, which is considered to be offset from the planet's center; the magnetopause currents driven by the solar wind; and the tail current system including the cross-tail currents and their closure currents
Journal of Geophysical Research: Space Physics, 1996
The magnetospheric magnetic field is highly time‐dependent and may have explosive changes (magnet... more The magnetospheric magnetic field is highly time‐dependent and may have explosive changes (magnetospheric substorms and geomagnetic storms) accompanied by significant energy input into the magnetosphere. However, the existing stationary magnetospheric models can not simulate the magnetosphere for disturbed conditions associated with the most interesting magnetospheric physics events (intensive auroras, particle injection in the inner magnetosphere, and precipitations at the high latitudes, etc.). We propose a method for constructing a nonstationary model of the magnetospheric magnetic field, which enables us to describe the magnetosphere during the disturbances. The dynamic changes of the magnetosphere will be represented as a sequence of quasistationary states. The relative contributions to the Dst index by various sources of magnetospheric magnetic field are considered using a dynamic model of the Earth's magnetosphere. The calculated magnetic field is obtained by using the so...
Journal of Geophysical Research: Space Physics, 2001
The dynamics of the magnetospheric current systems are studied in the course of the specific magn... more The dynamics of the magnetospheric current systems are studied in the course of the specific magnetospheric disturbance on January 9–12, 1997, caused by the interaction of the Earth's magnetosphere with a dense solar wind plasma cloud. To estimate the contribution of the different sources of the magnetospheric magnetic field to the disturbance ground measured, a dynamic paraboloid model of the magnetosphere is used. The model input parameters are defined by the solar wind density and velocity, by the strength and direction of the interplanetary magnetic field, and by the auroral AL index. The total energy of the ring current particles is calculated from the energy balance equation, where the injection function is determined by the value of the solar wind electric field. New analytical relations describing the dynamics of the different magnetospheric magnetic field sources dependent on the model input parameters are obtained. The analysis of the magnetic disturbances during the J...
A re‐scaling of a recent model of Jupiter's magnetosphere incorporating ring current, magneto... more A re‐scaling of a recent model of Jupiter's magnetosphere incorporating ring current, magnetopause, and tail current systems is used as a starting‐point for modeling Saturn's magnetospheric field. The model is compared with observations obtained by Cassini during its Saturn orbit insertion fly‐through of Saturn's magnetosphere, and is shown to give a good description. Comparison of ring current parameters obtained on the inbound and early outbound passes, when the magnetosphere was expanded due to low solar wind pressure, with those obtained by Voyager‐1 under more usual conditions, and by Pioneer‐11 when the magnetosphere was compressed, suggests that the ring current magnetic moment increases with system size. The effect is proposed to be due to radial stress balance conditions in a rapidly rotating magnetosphere, and has consequences for the dependence of magnetosphere size on solar wind pressure.
We present simulations of the terrestrial and Martian paleo-magnetosphere for ~4.1-4.0 billion ye... more We present simulations of the terrestrial and Martian paleo-magnetosphere for ~4.1-4.0 billion years (Gyr) ago, which were performed with adapted versions of the Paraboloid Magnetospheric Model (PMM) of the Skobeltsyn Institute for Nuclear Physics of the Moscow State University. For the Earth our simulations show that the paleo-magnetosphere was significantly smaller than today, with a standoffdistance rs ranging from ~3.4 to ~8.2 Re, depending on the chosen input parameters. Our simulations also show that the Martian paleo-magnetosphere should have been comparable in size to the terrestrial paleomagnetosphere until its cessation ~4.0 Gyr ago. At Earth, a nitrogen-dominated atmosphere would not have survived the harsh conditions during the late Hadean eon, i.e. ~4.1 Gyr ago, whereas a CO2dominated atmosphere could have survived. Further implications for the ancient atmospheres of Earth and Mars will be discussed.
Journal of Geophysical Research: Space Physics, 2015
We investigate the magnetic perturbations associated with field‐aligned currents observed on 34 C... more We investigate the magnetic perturbations associated with field‐aligned currents observed on 34 Cassini passes over the premidnight northern auroral region during 2008. These are found to be significantly modulated not only by the northern planetary‐period oscillation (PPO) system, similar to the southern currents by the southern PPO system found previously, but also by the southern PPO system as well, thus providing the first clear evidence of PPO‐related interhemispheric current flow. The principal field‐aligned currents of the two PPO systems are found to be co‐located in northern ionospheric colatitude, together with the currents of the PPO‐independent (subcorotation) system, located between the vicinity of the open‐closed field boundary and field lines mapping to ~9 Saturn radius (Rs) in the equatorial plane. All three systems are of comparable magnitude, ~3 MA in each PPO half‐cycle. Smaller PPO‐related field‐aligned currents of opposite polarity also flow in the interior regi...
Journal of Geophysical Research: Space Physics, 2015
A thin current sheet (TCS), with the width of an order of thermal proton gyroradius, appears a fu... more A thin current sheet (TCS), with the width of an order of thermal proton gyroradius, appears a fundamental physical object which plays an important role in structuring of major magnetospheric current systems (magnetotail, magnetodisk, etc.). The TCSs are nowadays under extensive study by means of space missions and theoretical models. We consider a simple model of the TCS separating two half‐spaces occupied by a homogenous magnetic field of opposite sign tangential to the TCS; a small normal component of the magnetic field is prescribed. An analytical solution for the electric current and plasma density in the close vicinity of the TCS has been obtained and compared with numerical simulation. The number density and the electric current profiles have two maxima each. The characteristic spatial scale zS of the maxima location was investigated as a function of initial pitch angle of an incoming charge particle. The effect of the thermal dispersion of the incoming proton beam have been ...
First we discuss the solar wind plasma interaction with the Solar System planets that have intrin... more First we discuss the solar wind plasma interaction with the Solar System planets that have intrinsic magnetic fields : Mercury , Earth , Jupiter , and Saturn are discussed. As a result of such an interaction cavities, which are free from the solar wind plasma and occupied by the planetary magnetic field are created. These cavities are usually called magnetospheres are surrounded and bound by the magnetopause . The magnetopause preserved the planetary magnetic field penetration into the magnetosheath so that its impossible for the magnetosheath plasma flow to penetrate into the magnetosphere. The magnetosheath are placed between the bow shock and the magnetopause. The bow shock forms a boundary against the unshocked super Alvenic plasma flow. As demonstrated by the analysis of the Mercury, Earth, Jupiter, and Saturn magnetopauses, these surfaces can be well described by a paraboloid of revolution with different subsolar distances and flaring angles. Based on this fact an universal model of the planetary magnetosphere can be constructed. We chose the planets in the inner magnetospheres of which the magnetic field vectors have been measured by orbiting spacecraft magnetometers. The proposed models describe the basic physical processes that are responsible for the structure and dynamics of the planetary magnetospheres . Additionally to the inner planetary field the different magnetospheric sources of magnetic field are included in the model. Finally, we discuss how these magnetosphere models can be applied to exoplanets in a comparative way.
Journal of Geophysical Research: Space Physics, 2008
A new “Paraboloidal” model of Mercury's magnetospheric magnetic fiel... more A new “Paraboloidal” model of Mercury's magnetospheric magnetic field based upon the earlier terrestrial model and using similar techniques is developed. The model describes the field of Mercury's dipole, which is considered to be offset from the planet's center; the magnetopause currents driven by the solar wind; and the tail current system including the cross-tail currents and their closure currents
Journal of Geophysical Research: Space Physics, 1996
The magnetospheric magnetic field is highly time‐dependent and may have explosive changes (magnet... more The magnetospheric magnetic field is highly time‐dependent and may have explosive changes (magnetospheric substorms and geomagnetic storms) accompanied by significant energy input into the magnetosphere. However, the existing stationary magnetospheric models can not simulate the magnetosphere for disturbed conditions associated with the most interesting magnetospheric physics events (intensive auroras, particle injection in the inner magnetosphere, and precipitations at the high latitudes, etc.). We propose a method for constructing a nonstationary model of the magnetospheric magnetic field, which enables us to describe the magnetosphere during the disturbances. The dynamic changes of the magnetosphere will be represented as a sequence of quasistationary states. The relative contributions to the Dst index by various sources of magnetospheric magnetic field are considered using a dynamic model of the Earth's magnetosphere. The calculated magnetic field is obtained by using the so...
Journal of Geophysical Research: Space Physics, 2001
The dynamics of the magnetospheric current systems are studied in the course of the specific magn... more The dynamics of the magnetospheric current systems are studied in the course of the specific magnetospheric disturbance on January 9–12, 1997, caused by the interaction of the Earth's magnetosphere with a dense solar wind plasma cloud. To estimate the contribution of the different sources of the magnetospheric magnetic field to the disturbance ground measured, a dynamic paraboloid model of the magnetosphere is used. The model input parameters are defined by the solar wind density and velocity, by the strength and direction of the interplanetary magnetic field, and by the auroral AL index. The total energy of the ring current particles is calculated from the energy balance equation, where the injection function is determined by the value of the solar wind electric field. New analytical relations describing the dynamics of the different magnetospheric magnetic field sources dependent on the model input parameters are obtained. The analysis of the magnetic disturbances during the J...
A re‐scaling of a recent model of Jupiter's magnetosphere incorporating ring current, magneto... more A re‐scaling of a recent model of Jupiter's magnetosphere incorporating ring current, magnetopause, and tail current systems is used as a starting‐point for modeling Saturn's magnetospheric field. The model is compared with observations obtained by Cassini during its Saturn orbit insertion fly‐through of Saturn's magnetosphere, and is shown to give a good description. Comparison of ring current parameters obtained on the inbound and early outbound passes, when the magnetosphere was expanded due to low solar wind pressure, with those obtained by Voyager‐1 under more usual conditions, and by Pioneer‐11 when the magnetosphere was compressed, suggests that the ring current magnetic moment increases with system size. The effect is proposed to be due to radial stress balance conditions in a rapidly rotating magnetosphere, and has consequences for the dependence of magnetosphere size on solar wind pressure.
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Papers by E. Belenkaya