scholarly journals Propagation of ULF waves from the upstream region to the midnight sector of the inner magnetosphere

2016 ◽  
Vol 121 (9) ◽  
pp. 8428-8447 ◽  
Author(s):  
Kazue Takahashi ◽  
Michael D. Hartinger ◽  
David M. Malaspina ◽  
Charles W. Smith ◽  
Kiyokazu Koga ◽  
...  
Keyword(s):  
Upstream Region ◽  
Ulf Waves ◽  
Inner Magnetosphere

scholarly journals Modulation of chorus intensity by ULF waves deep in the inner magnetosphere

2016 ◽  
Vol 43 (18) ◽  
pp. 9444-9452 ◽  
Author(s):  
Zhiyang Xia ◽  
Lunjin Chen ◽  
Lei Dai ◽  
Seth G. Claudepierre ◽  
Anthony A. Chan ◽  
...  
Keyword(s):  
Ulf Waves ◽  
Inner Magnetosphere

Modulation of the solar wind driven ion escape from unmagnetized planets by ultra-low-frequency foreshock waves in a global hybrid simulation

2020 ◽  
Author(s):  
Riku Jarvinen ◽  
Esa Kallio ◽  
Tuija Pulkkinen
Keyword(s):  
Solar Wind ◽  
Large Scale ◽  
Low Frequency ◽  
Hybrid Simulation ◽  
Bow Shock ◽  
Upstream Region ◽  
Ulf Waves ◽  
Solar Wind Interaction ◽  
Ion Escape ◽  
A Charge

<p>We study the solar wind interaction with Venus in a 3-dimensional global hybrid model where ions are treated as particles and electrons are a charge-neutralizing fluid. We concentrate on large-scale ultra-low frequency (ULF) waves in the ion foreshock and how they affect the energization and escape of planetary ions. The ion foreshock forms in the upstream region ahead of the quasi-parallel bow shock, where the angle between the shock normal and the magnetic field is smaller than about 45 degrees. The magnetic connection with the bow shock allows backstreaming of the solar wind ions leading to the formation of the ion foreshock. This kind of beam-plasma configuration is a source of free energy for the excitation of plasma waves. The foreshock ULF waves convect downstream with the solar wind flow and encounter the bow shock and transmit in the downstream region. We analyze the coupling of the ULF waves with the planetary ion acceleration and compare Venus and Mars in a global hybrid simulation.</p>

Roles of magnetospheric convection on nonlinear drift resonance between electrons and ULF waves

2020 ◽  
Author(s):  
Xuzhi Zhou ◽  
Li Li ◽  
Yoshiharu Omura ◽  
Qiugang Zong ◽  
Suiyan Fu ◽  
...  
Keyword(s):  
Distribution Functions ◽  
Ulf Waves ◽  
Inner Magnetosphere ◽  
Ultralow Frequency ◽  
Magnetospheric Convection ◽  
Ulf Wave ◽  
Pendulum Equation ◽  
Drift Frequency ◽  
Strong Convection ◽  
Trapping Frequency

<p>In the Earth's inner magnetosphere, charged particles can be accelerated and transported by ultralow frequency (ULF) waves via drift resonance. We investigate the effects of magnetospheric convection on the nonlinear drift resonance process, which provides an inhomogeneity factor S to externally drive the pendulum equation that describes the particle motion in the ULF wave  field. The S factor, defined as the ratio of the driving amplitude to the square of the pendulum trapping frequency, is found to vary with magnetic local time and as a consequence, oscillates quasi-periodically at the particle drift frequency. To better understand the particle behavior governed by the driven pendulum equation, we carry out simulations to obtain the evolution of electron distribution functions in energy and L-shell phase space. We find that resonant electrons can remain trapped by the low-m ULF waves under strong convection electric  field, whereas for high-m ULF waves, the electrons trajectories can be significantly modified. More interestingly, the electron drift frequency is close to the nonlinear trapping frequency for intermediate-m ULF waves, which corresponds to chaotic motion of resonant electrons. These  findings shed new light on the nature of particle coherent and diffusive transport in the inner magnetosphere.</p>

Ultra-Low Frequency (ULF) waves originating in solar wind dynamic pressure oscillations and propagating through the magnetosheath to the inner magnetosphere

2020 ◽  
Author(s):  
Marina Georgiou ◽  
Christos Katsavrias ◽  
Ioannis Daglis ◽  
Georgios Balasis
Keyword(s):  
Solar Wind ◽  
Wavelet Transform ◽  
Dynamic Pressure ◽  
Solar Wind Dynamic Pressure ◽  
Slow Solar Wind ◽  
Ulf Waves ◽  
Pressure Oscillations ◽  
Inner Magnetosphere ◽  
Cross Wavelet ◽  
Wave Properties

<p>Several observational studies have shown that ULF oscillations of the solar wind dynamic pressure can drive periodic fluctuations in magnetic field measurements at corresponding frequencies. In this study, we use multi-spacecraft (Cluster, GOES, THEMIS and Van Allen Probes) mission measurements to investigate the propagation of pressure fluctuations-driven pulsations within the Pc5 and Pc4 frequency range (from ~0.5 to 25 mHz) into the magnetosphere. During intervals of slow solar wind — to exclude waves generated by velocity shear at the magnetopause — common periodicities in electromagnetic fields in the magnetosphere and the solar wind driver are first detected in Lomb-Scargle periodograms. Then, using the cross-wavelet transform, we examine the causal relationship and specifically, in cross-wavelet spectra and wavelet transform coherence. Lastly, spatial and temporal variations of wave properties are mapped from beyond the magnetopause to the inner magnetosphere through frequency, polarisation and power signatures of waves detected at the various probes. The observed dependence of wave properties on their localisation offers an excellent source for verification of the role that solar wind dynamic pressure oscillations as driver of ULF waves propagating through the magnetosheath into the dayside and nightside magnetosphere.</p>

Presence of cavity resonances in the inner magnetosphere

2020 ◽  
Author(s):  
Harri Laakso
Keyword(s):  
Geomagnetic Activity ◽  
Radiation Belt ◽  
Wave Mode ◽  
Cavity Resonance ◽  
Ulf Waves ◽  
Inner Magnetosphere ◽  
Half Wavelength ◽  
Cavity Resonances ◽  
String Of Pearls

<p>In the inner magnetosphere there are sharp plasma boundaries that can cause resonance cavities. The four Cluster satellites move in a string-of-pearls configuration at perigee (at L=4-5) so that they are spatially well separated but their separation is still short that at least some of them are simultaneously at different positions inside the cavity. In the presence of cavity resonance of a half wavelength, all spacecraft inside the cavity observe the same wave mode in the same phase. In this talk we analyze and present a number of cavity resonances observed by the Cluster spacecraft. Typical observed mode frequencies are between 4 - 14 mHz, depending on the size of the cavity. It appears that the occurrence of cavity resonances is well correlated with changes in geomagnetic activity and they are quite common. They tend to occur at 12-16 MLT and 21-23 MLT. These ULF waves may have a significant impact on radiation belt particles as they cover a large L shell range.</p>

Storm time occurrence and spatial distribution of Pc4 poloidal ULF waves in the inner magnetosphere: A Van Allen Probes statistical study

2015 ◽  
Vol 120 (6) ◽  
pp. 4748-4762 ◽  
Author(s):  
Lei Dai ◽  
Kazue Takahashi ◽  
Robert Lysak ◽  
Chi Wang ◽  
John R. Wygant ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Statistical Study ◽  
Ulf Waves ◽  
Inner Magnetosphere ◽  
Van Allen Probes

Ultra-low frequency foreshock waves at Venus and Mercury in a global hybrid simulation

2020 ◽  
Author(s):  
Riku Jarvinen ◽  
Esa Kallio ◽  
Tuija I. Pulkkinen
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Large Scale ◽  
Low Frequency ◽  
Hybrid Simulation ◽  
Bow Shock ◽  
Upstream Region ◽  
Ulf Waves ◽  
Solar Wind Interaction ◽  
Low Frequency Waves

<p>We study the solar wind interaction with Venus and Mercury in a 3-dimensional global hybrid simulation where ions are treated as particles and electrons are a charge-neutralizing fluid. We concentrate on the formation of large-scale ultra-low frequency (ULF) waves in ion foreshocks and their dependence on the solar wind and interplanetary magnetic field conditions. The ion foreshock forms in the upstream region ahead of the quasi-parallel bow shock, where the angle between the shock normal and the magnetic field is smaller than about 45 degrees. The magnetic connection with the bow shock allows backstreaming of the solar wind ions leading to the formation of the ion foreshock. This kind of beam-plasma configuration is a source of free energy for the excitation of plasma waves. The foreshock ULF waves convect downstream with the solar wind flow and encounter the bow shock. We compare the waves between Venus and Mercury, and analyze the coupling of the ULF waves with the planetary ion acceleration at Venus.</p> <p>References:</p> <p>Jarvinen R., Alho M., Kallio E., Pulkkinen T.I., 2020, Oxygen Ion Escape From Venus Is Modulated by Ultra-Low Frequency Waves, Geophys. Res. Lett., 47, 11, doi:10.1029/2020GL087462</p> <p>Jarvinen R., Alho M., Kallio E., Pulkkinen T.I., 2020, Ultra-low frequency waves in the ion foreshock of Mercury: A global hybrid modeling study, Mon. Notices Royal Astron. Soc., 491, 3, 4147-4161, doi:10.1093/mnras/stz3257</p>

scholarly journals Fast acceleration of “killer” electrons and energetic ions by interplanetary shock stimulated ULF waves in the inner magnetosphere

2011 ◽  
Vol 56 (12) ◽  
pp. 1188-1201 ◽  
Author(s):  
QiuGang Zong ◽  
YongFu Wang ◽  
ChongJing Yuan ◽  
Biao Yang ◽  
ChenRui Wang ◽  
...  
Keyword(s):  
Interplanetary Shock ◽  
Ulf Waves ◽  
Energetic Ions ◽  
Inner Magnetosphere

The Role of Solar Wind Structures in the Generation of ULF Waves in the Inner Magnetosphere

Solar Physics ◽  
2017 ◽  
Vol 292 (7) ◽  
Author(s):  
L. R. Alves ◽  
V. M. Souza ◽  
P. R. Jauer ◽  
L. A. da Silva ◽  
C. Medeiros ◽  
...  
Keyword(s):  
Solar Wind ◽  
Ulf Waves ◽  
Inner Magnetosphere

scholarly journals Cold Plasmaspheric Electrons Affected by ULF Waves in the Inner Magnetosphere: A Van Allen Probes Statistical Study

2019 ◽  
Vol 124 (10) ◽  
pp. 7954-7965 ◽  
Author(s):  
Jie Ren ◽  
Q. G. Zong ◽  
X. Z. Zhou ◽  
H. E. Spence ◽  
H. O. Funsten ◽  
...  
Keyword(s):  
Statistical Study ◽  
Ulf Waves ◽  
Inner Magnetosphere ◽  
Van Allen Probes
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