Inward diffusion driven by low frequency fluctuations in self-organizing magnetospheric plasma

The new findings for dynamic process of inward diffusion in the magnetospheric plasma are reported on the RT-1 experiment: (i) The evolution of local density profile in the self-organized process has been analysed by the newly developed tomographic reconstruction applying a deep learning method. (ii) The impact of neutral-gas injection excites low-frequency fluctuations, which continues until the peaked density profile recovers. The fluctuations have magnetic components (suggesting the high-beta effect) which have two different frequencies and propagation directions. The phase velocities are of the order of magnetization drifts, and both the velocities and the intensities increase in proportion to the electron density. The self-regulating mechanism of density profile works most apparently in the naturally made confinement system, magnetosphere, which teaches the basic physics of long-lived structures underlying every stationary confinement scheme.

Laboratory modeling of a field-aligned currents system generated by a flow of inner magnetospheric plasma

For the first time in laboratory conditions, an experiment to simulate a system of field-aligned currents arising on planets such as Hot Jupiters in the presence of dense inner-magnetospheric plasma was carried out. The magnitude and transit time of field-aligned currents were measured as a function of the magnetic field using flat electrodes. The geometry of the expansion of plasma streams was pictured by gated camera. Also, in a first approximation, the efficiency of energy transfer from plasma flows to field-aligned currents was calculated. The results obtained create a basis for future laboratory experiments on this topic and improve existing numerical models.

The Key Role of Cold Ionospheric Ions As a Source of Hot Magnetospheric Plasma and As a Driver of the Dynamics of Substorms and Storms

The solar wind has been seen as the major source of hot magnetospheric plasma since the early 1960’s. More recent theoretical and observational studies have shown that the cold (few eV) polar wind and warmer polar cusp plasma that flow continuously upward from the ionosphere can be a very significant source of ions in the magnetosphere and can become accelerated to the energies characteristic of the plasma sheet, ring current, and warm plasma cloak. Previous studies have also shown the presence of solar wind ions in these magnetospheric regions. These studies are based principally on proxy measurements of the ratios of He++/H+ and the high charge states of O+/H+. The resultant admixture of ionospheric ions and solar wind ions that results has been difficult to quantify, since the dominant H+ ions originating in the ionosphere and solar wind are indistinguishable. The ionospheric ions are already inside the magnetosphere and are filling it from the inside out with direct access from the ionosphere to the center of the magnetotail. The solar wind ions on the other hand must gain access through the outer boundaries of the magnetosphere, filling the magnetosphere from the outside in. These solar wind particles must then diffuse or drift from the flanks of the magnetosphere to the near-midnight reconnection region of the tail which takes more time to reach (hours) than the continuously large outflowing ionospheric polar wind (10’s of min). In this paper we examine the magnetospheric filling using the trajectories of the different ion sources to unravel the intermixing process rather than trying to interpret only the proxy ratios. We compare the timing of the access of the ionospheric and solar wind sources and we use new merged ionosphere-magnetosphere multi-fluid MHD modeling to separate and compare the ionospheric and solar wind H+ source strengths. The rapid access of the initially cold polar wind and warm polar cusp ions flowing down-tail in the lobes into the mid-plane of the magnetotail, suggests that, coupled with a southward turning of the IMF Bz, these ions can play a key triggering role in the onset of substorms and subsequent large storms.

On the Impacts of Ions of Ionospheric Origin and Their Composition on Magnetospheric EMIC Waves

Large numbers of theory and observation studies have been conducted on electromagnetic ion cyclotron (EMIC) waves occurring in Earth’s magnetosphere. Numerous studies have shown that accurately specifying the ions of ionospheric origin and their composition can greatly improve understanding of magnetospheric EMIC waves, specifically their generation, their properties, and their effects on the magnetospheric plasma populations. With the launch and operations of multiple recent missions carrying plasma instrumentation capable of acquiring direct measurements of multiple ion species, we use this opportunity to review recent magnetospheric EMIC wave efforts utilizing these new assets, with particular focus on the role of ions of ionospheric origin in wave generation, propagation, and interaction with particles. The review of progress leads us to a discussion of the unresolved questions to be investigated using future modeling capabilities or when new missions or instrumentation capabilities are developed.

On the simultaneous generation of radio and soft X-ray emission by AXP 4U 0142+61

In the present paper we study the possibility of a simultaneous generation of radio waves and soft X-rays by means of the quasi-linear diffusion (QLD) in the anomalous pulsar AXP 4U 0142+61. Considering the magnetosphere composed of the so-called beam component and the plasma component respectively, we argue that the frozen-in condition will inevitably lead to the generation of the unstable cyclotron waves. These waves, via the QLD, will in turn influence the particle distribution function, leading to certain values of the pitch angles, thus to an efficient synchrotron mechanism, producing soft X-ray photons. We show that for physically reasonable parameters of magnetospheric plasma, the QLD can provide generation of radio waves in the following interval 40 MHz - 111 MHz connected to soft X-rays for the domain 0.3 keV - 1.4 keV.