scholarly journals Helium in the Earth's foreshock: a global Vlasiator survey

2020 ◽  
Author(s):  
Markus Battarbee ◽  
Xóchitl Blanco-Cano ◽  
Lucile Turc ◽  
Primoz Kajdic ◽  
Vertti Tarvus ◽  
...  
Keyword(s):  
Low Frequency ◽  
Alpha Particles ◽  
Compressive Wave ◽  
Energetic Ions ◽  
Ion Distributions ◽  
Hot Plasma ◽  
Earth’S Bow Shock ◽  
Composition Analyzer ◽  
Ion Profiles ◽  
Low Frequency Waves

<p>The foreshock is a region of space in front of the Earth's bow shock, extending along the interplanetary magnetic field. It is permeated by ions and electrons reflected at the shock, low-frequency waves, and various plasma transients. The ion foreshock is dominated by a number of proton populations such as field-aligned beams, gyrating distributions and diffuse ions, as well as proton-excited waves. As the solar wind can contain a significant fraction of helium, it is of great interest to investigate how alpha-particles (He<sup>2+</sup>) are reflected into forming their own foreshock. We investigate the extent of the helium foreshock in relation to foreshock ultra-low frequency waves and protons using Vlasiator, a global hybrid-Vlasov simulation. We confirm a number of historical spacecraft observations at the foreshock regions associated with field-aligned beams, gyrating ion distributions, and specularly reflected particles, performing the first numerical global survey of the helium foreshock. We present wavelet analysis at multiple positions within the foreshock and evaluate the dynamics of gyrating ion populations in response to the transverse and compressive wave components. We also present Magnetosphere Multiscale (MMS) spacecraft crossings of the foreshock edge and compare Hot Plasma Composition Analyzer (HPCA) measurements of energetic ions with our simulation data, showing the variability of the foreshock edge suprathermal ion profiles.</p>

WIND observation of gyrating-like ion distributions and low frequency waves upstream from the Earth's bow shock

1997 ◽  
Vol 20 (4-5) ◽  
pp. 703-706 ◽  
Author(s):  
K. Meziane ◽  
C. Mazelle ◽  
C. d'Uston ◽  
H. Rème ◽  
R.P. Lin ◽  
...  
Keyword(s):  
Low Frequency ◽  
Bow Shock ◽  
Wind Observation ◽  
Ion Distributions ◽  
Earth’S Bow Shock ◽  
Low Frequency Waves

Low-frequency waves and associated energetic ions downstream of Saturn

1985 ◽  
Vol 90 (A11) ◽  
pp. 10791 ◽  
Author(s):  
K. W. Behannon ◽  
M. L. Goldstein ◽  
R. P. Lepping ◽  
H. K. Wong ◽  
B. H. Mauk ◽  
...  
Keyword(s):  
Low Frequency ◽  
Energetic Ions ◽  
Low Frequency Waves

Ultra low frequency waves at the Earth's bow shock

1995 ◽  
Vol 15 (8-9) ◽  
pp. 285-296 ◽  
Author(s):  
C.T Russell ◽  
M.H Farris
Keyword(s):  
Low Frequency ◽  
Bow Shock ◽  
Earth’S Bow Shock ◽  
Low Frequency Waves

scholarly journals Helium in the Earth's foreshock: a global Vlasiator survey

2020 ◽  
Vol 38 (5) ◽  
pp. 1081-1099
Author(s):  
Markus Battarbee ◽  
Xóchitl Blanco-Cano ◽  
Lucile Turc ◽  
Primož Kajdič ◽  
Andreas Johlander ◽  
...  
Keyword(s):  
Specular Reflection ◽  
Cone Angle ◽  
Low Frequency ◽  
Velocity Distribution Function ◽  
Bow Shock ◽  
Wave Interactions ◽  
Ulf Wave ◽  
Hot Plasma ◽  
Earth’S Bow Shock ◽  
Ion Velocity Distribution Function

Abstract. The foreshock is a region of space upstream of the Earth's bow shock extending along the interplanetary magnetic field (IMF). It is permeated by shock-reflected ions and electrons, low-frequency waves, and various plasma transients. We investigate the extent of the He2+ foreshock using Vlasiator, a global hybrid-Vlasov simulation. We perform the first numerical global survey of the helium foreshock and interpret some historical foreshock observations in a global context. The foreshock edge is populated by both proton and helium field-aligned beams, with the proton foreshock extending slightly further into the solar wind than the helium foreshock and both extending well beyond the ultra-low frequency (ULF) wave foreshock. We compare our simulation results with Magnetosphere Multiscale (MMS) Hot Plasma Composition Analyzer (HPCA) measurements, showing how the gradient of suprathermal ion densities at the foreshock crossing can vary between events. Our analysis suggests that the IMF cone angle and the associated shock obliquity gradient can play a role in explaining this differing behaviour. We also investigate wave–ion interactions with wavelet analysis and show that the dynamics and heating of He2+ must result from proton-driven ULF waves. Enhancements in ion agyrotropy are found in relation to, for example, the ion foreshock boundary, the ULF foreshock boundary, and specular reflection of ions at the bow shock. We show that specular reflection can describe many of the foreshock ion velocity distribution function (VDF) enhancements. Wave–wave interactions deep in the foreshock cause de-coherence of wavefronts, allowing He2+ to be scattered less than protons.

Low-frequency waves in inhomogeneous magnetic fields

1979 ◽  
Vol 21 (2) ◽  
pp. 279-286 ◽  
Author(s):  
A. Hruška
Keyword(s):  
Low Frequency ◽  
Sound Waves ◽  
Isotropic Plasma ◽  
Phase Velocities ◽  
Magnetic Field Topology ◽  
Hot Plasma ◽  
Propagation Of Waves ◽  
The Magnetic Field ◽  
Low Frequency Waves ◽  
Scale Length

Propagation of waves in inhomogeneous, hot, isotropic plasma is described, assuming that the wavelength is much smaller than the scale-length of the plasma. The effect of the magnetic field topology on properties of waves is discussed in some detail. Coupling between the modes of oscillations is always present in an inhomogeneous ‘hot’ plasma. It is particularly strong for magneto- dynamic and sound waves propagating essentially along the fleidlines in the vicinity of a point where the phase velocities of the two modes are equal.

scholarly journals Helium in the Earth’s foreshock: a global Vlasiator survey

2020 ◽  
Author(s):  
Markus Battarbee ◽  
Xochitl Blanco-Cano ◽  
Lucile Turc ◽  
Primož Kajdič ◽  
Andreas Johlander ◽  
...  
Keyword(s):  
Specular Reflection ◽  
Cone Angle ◽  
Low Frequency ◽  
Bow Shock ◽  
Wave Interactions ◽  
Global Context ◽  
Ulf Wave ◽  
Ion Interactions ◽  
Earth’S Bow Shock ◽  
Low Frequency Waves

Abstract. The foreshock is a region of space upstream of the Earth's bow shock extending along the interplanetary magnetic field. It is permeated by shock-reflected ions and electrons, low-frequency waves, and various plasma transients. We investigate the extent of the He2+ foreshock using Vlasiator, a global hybrid-Vlasov simulation. We perform the first numerical global survey of the helium foreshock, and interpret some historical foreshock observations in a global context. The foreshock edge is populated by both proton and helium field-aligned beams, with the proton foreshock extending slightly further into the solar wind than the helium foreshock, and both extend well beyond the ULF wave foreshock. We compare our simulation results with MMS HPCA measurements, showing how the gradient of suprathermal ion densities at the foreshock crossing can vary between events. Our analysis suggests that the IMF cone angle and the associated shock obliquity gradient can play a role in explaining this differing behaviour. We also investigate wave-ion-interactions with wavelet analysis and show that the dynamics and heating of He2+ must result from proton-driven ULF waves. Enhancements in ion agyrotropy are found in relation to, e.g., the ion foreshock boundary, the ULF foreshock boundary, and specular reflection of ions at the bow shock. We show that specular reflection can describe many of the foreshock ion VDF enhancements. Wave-wave-interactions deep in the foreshock cause decoherence of wavefronts, allowing He2+ the be scattered less than protons.

PEMANFAATAN RADIASI ENERGI TEGANGAN 150 KV UNTUK LAMPU LED PENERANGAN JALAN

Jurnal Teknik ◽  
2018 ◽  
Vol 7 (1) ◽  
Author(s):  
Mauludi Manfaluthy
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
High Voltage ◽  
Low Frequency ◽  
Energy Utilization ◽  
World Health ◽  
Electromagnetic Signals ◽  
Health Organization ◽  
The Magnetic Field ◽  
Low Frequency Waves

WHO (World Health Organization) concludes that not much effect is caused by electric field up to 20 kV / m in humans. WHO standard also mentions that humans will not be affected by the magnetic field under  100 micro tesla and that the electric field will affect the human body with a maximum standard of 5,000 volts per meter. In this study did not discuss about the effect of high voltage radiation SUTT (High Voltage Air Channel) with human health. The research will focus on energy utilization of SUTT radiation. The combination of electric field and magnetic field on SUTT (70-150KV) can generate electromagnetic (EM) and radiation waves, which are expected to be converted to turn on street lights around the location of high voltage areas or into other forms. The design of this prototype works like an antenna in general that captures electromagnetic signals and converts them into AC waves. With a capacitor that can store the potential energy of AC and Schottky diode waves created specifically for low frequency waves, make the current into one direction (DC). From the research results obtained the current generated from the radiation is very small even though the voltage is big enough.Keywords : Radiance Energy, Joule Thief, and  LED Module.

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