A theoretical study of magnetic-field reconnection in the magnetotail is presented. It is shown t... more A theoretical study of magnetic-field reconnection in the magnetotail is presented. It is shown that reconnection leads to the formation of two FR regions, one of which moves toward the earth while the other moves into the magnetotail, transporting magnetic flux and plasma accelerated to Alfven velocity.
In this article we address several criticisms of Petschek-type reconnection models which have rec... more In this article we address several criticisms of Petschek-type reconnection models which have recently been raised by Heikkila. We discuss features of the time-dependent Petschek-type models in the context of the solar wind-magnetosphere interaction, and point out that such models can incorporate and reproduce observed features at the magnetopause, such as plasma jets and erosion of the current sheet. We argue that some of Heikkila's criticisms can be attributed to weaknesses in the analysis due to incomplete experimental information, rather than to flaws in the concept of reconnection per se; in this category we include the question of which instability leads to the localised breakup of the magnetopause current sheet. Other criticisms are based on an adherence to steady-state models, and cannot be sustained within the extended time-dependent theory. We discuss, for example, how the time-dependent model can provide a consistent picture of how energy from the incoming solar wind...
The Moon does not have a global magnetic field. However, the lunar crust contains regions of rema... more The Moon does not have a global magnetic field. However, the lunar crust contains regions of remanent magnetization which are strong enough to deflect and reflect a substantial part of the incoming solar wind ions.Such effects as lunar swirls, limb shocks, minimagnetospheres, low-frequency waves are the global processes induced by the local magnetic fields. In this work we investigate the correlation between local magnetic field data provided by the Tsunakawa model [2015], and the total particle reflectionfunction estimated by Lueet al.[2011]. We find a spatial correlation coefficient between those two up to ~0.7 for the magnetic field model value at 20 km. It was found that an increase in the field leads to a significant increase in reflection and this dependence of the field on the reflection coefficient has a clear nonlinear form, which is consistent with numerical simulation results that show more intense scattering for stronger magnetic anomalies. For low magnetic field regions...
Abstract. In the frame of magnetized plasmas, reconnection appears as an essential process for th... more Abstract. In the frame of magnetized plasmas, reconnection appears as an essential process for the description of plasma acceleration and changing magnetic field topology. Under the variety of reconnection regions in our solar system, we focus our research onto the Earth’s magnetotail. Under certain conditions a Near Earth Neutral Line (NENL) is free to evolve in the current sheet of the magnetotail. Reconnection in this region leads to the formation of Earth- and tailward propagating plasma bulges, which can be detected by the Cluster or Geotail spacecraft. Observations give rise to the assumption that the evolved reconnection line does not provide a steady state behavior, but is propagating towards the tail (e.g., Baker et al., 2002). Based on a time-dependent variant of the Petschek model of magnetic reconnection, we present a method that includes an X-line motion and discuss the effects of such a motion. We focus our main interest on the shock structure and the magnetic field be...
ABSTRACT A rigorous theoretical analysis of the reconnection process in a three-dimensional incom... more ABSTRACT A rigorous theoretical analysis of the reconnection process in a three-dimensional incompressible Sonnerup model is presented. The input data for the model consisted of the position of a current sheet with magnitude fields and flows on either side. The specific physical conditions for the initiation of the reconnection process are identified, and the sheet components lying parallel to the reconnection line are obtained from the solution of a two-dimensional problem. The solutions to the reconnection problem were subdivided into four classes, with two of the solutions corresponding to the magnetic force lines, and the remaining two corresponding to the current lines. The problem of determining the position of the reconnection line in the magnetopause is also considered.
Reconnection-linked features, produced by magnetotail reconnection, have been ob- served by Clust... more Reconnection-linked features, produced by magnetotail reconnection, have been ob- served by Cluster spacecraft for several times. These reconnection features give information about the process of magnetic reconnection. We present here a simple method to determine the essential parameters of reconnection such as reconnected flux, the reconnection rate and the location, where reconnection occurs, out of single spacecraft data via remote sensing. On the basis of a time-dependent reconnection model, the dependence of the reconnected flux on the magnetic field z-component Bz is shown. The integral of Bz over time is pro- portional to the reconnected flux and depends on the distance between the reconnection scene and the actual position where Bz is measured. This distance can be estimated, using a magnetotail model, and by analyzing measured magnetic field Bz amplitudes. With the location of the reconnection scene, the reconnected flux and after this, the reconnection rate can be determin...
We investigate model data produced by several close reconnection pulses. It is shown that a serie... more We investigate model data produced by several close reconnection pulses. It is shown that a series of such pulses tends to induce a clear trend in the time-evolution of x-and z-components of both, the magnetic field (B x , B z) and plasma velocity (v x , v z). Such signatures with a typical trend in time during pulse propagation occur only for moderate distances of the observer with respect to the current layer. In all other cases relatively close to the current layer, the observer will see the direct effect of every single pulse onto the behaviour of the in detail measured magnetic field and plasma velocity. On the other hand, far away, all pulses will join and will look like one single pulse in the observational data.
A theoretical study of magnetic-field reconnection in the magnetotail is presented. It is shown t... more A theoretical study of magnetic-field reconnection in the magnetotail is presented. It is shown that reconnection leads to the formation of two FR regions, one of which moves toward the earth while the other moves into the magnetotail, transporting magnetic flux and plasma accelerated to Alfven velocity.
In this article we address several criticisms of Petschek-type reconnection models which have rec... more In this article we address several criticisms of Petschek-type reconnection models which have recently been raised by Heikkila. We discuss features of the time-dependent Petschek-type models in the context of the solar wind-magnetosphere interaction, and point out that such models can incorporate and reproduce observed features at the magnetopause, such as plasma jets and erosion of the current sheet. We argue that some of Heikkila's criticisms can be attributed to weaknesses in the analysis due to incomplete experimental information, rather than to flaws in the concept of reconnection per se; in this category we include the question of which instability leads to the localised breakup of the magnetopause current sheet. Other criticisms are based on an adherence to steady-state models, and cannot be sustained within the extended time-dependent theory. We discuss, for example, how the time-dependent model can provide a consistent picture of how energy from the incoming solar wind...
The Moon does not have a global magnetic field. However, the lunar crust contains regions of rema... more The Moon does not have a global magnetic field. However, the lunar crust contains regions of remanent magnetization which are strong enough to deflect and reflect a substantial part of the incoming solar wind ions.Such effects as lunar swirls, limb shocks, minimagnetospheres, low-frequency waves are the global processes induced by the local magnetic fields. In this work we investigate the correlation between local magnetic field data provided by the Tsunakawa model [2015], and the total particle reflectionfunction estimated by Lueet al.[2011]. We find a spatial correlation coefficient between those two up to ~0.7 for the magnetic field model value at 20 km. It was found that an increase in the field leads to a significant increase in reflection and this dependence of the field on the reflection coefficient has a clear nonlinear form, which is consistent with numerical simulation results that show more intense scattering for stronger magnetic anomalies. For low magnetic field regions...
Abstract. In the frame of magnetized plasmas, reconnection appears as an essential process for th... more Abstract. In the frame of magnetized plasmas, reconnection appears as an essential process for the description of plasma acceleration and changing magnetic field topology. Under the variety of reconnection regions in our solar system, we focus our research onto the Earth’s magnetotail. Under certain conditions a Near Earth Neutral Line (NENL) is free to evolve in the current sheet of the magnetotail. Reconnection in this region leads to the formation of Earth- and tailward propagating plasma bulges, which can be detected by the Cluster or Geotail spacecraft. Observations give rise to the assumption that the evolved reconnection line does not provide a steady state behavior, but is propagating towards the tail (e.g., Baker et al., 2002). Based on a time-dependent variant of the Petschek model of magnetic reconnection, we present a method that includes an X-line motion and discuss the effects of such a motion. We focus our main interest on the shock structure and the magnetic field be...
ABSTRACT A rigorous theoretical analysis of the reconnection process in a three-dimensional incom... more ABSTRACT A rigorous theoretical analysis of the reconnection process in a three-dimensional incompressible Sonnerup model is presented. The input data for the model consisted of the position of a current sheet with magnitude fields and flows on either side. The specific physical conditions for the initiation of the reconnection process are identified, and the sheet components lying parallel to the reconnection line are obtained from the solution of a two-dimensional problem. The solutions to the reconnection problem were subdivided into four classes, with two of the solutions corresponding to the magnetic force lines, and the remaining two corresponding to the current lines. The problem of determining the position of the reconnection line in the magnetopause is also considered.
Reconnection-linked features, produced by magnetotail reconnection, have been ob- served by Clust... more Reconnection-linked features, produced by magnetotail reconnection, have been ob- served by Cluster spacecraft for several times. These reconnection features give information about the process of magnetic reconnection. We present here a simple method to determine the essential parameters of reconnection such as reconnected flux, the reconnection rate and the location, where reconnection occurs, out of single spacecraft data via remote sensing. On the basis of a time-dependent reconnection model, the dependence of the reconnected flux on the magnetic field z-component Bz is shown. The integral of Bz over time is pro- portional to the reconnected flux and depends on the distance between the reconnection scene and the actual position where Bz is measured. This distance can be estimated, using a magnetotail model, and by analyzing measured magnetic field Bz amplitudes. With the location of the reconnection scene, the reconnected flux and after this, the reconnection rate can be determin...
We investigate model data produced by several close reconnection pulses. It is shown that a serie... more We investigate model data produced by several close reconnection pulses. It is shown that a series of such pulses tends to induce a clear trend in the time-evolution of x-and z-components of both, the magnetic field (B x , B z) and plasma velocity (v x , v z). Such signatures with a typical trend in time during pulse propagation occur only for moderate distances of the observer with respect to the current layer. In all other cases relatively close to the current layer, the observer will see the direct effect of every single pulse onto the behaviour of the in detail measured magnetic field and plasma velocity. On the other hand, far away, all pulses will join and will look like one single pulse in the observational data.
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