scholarly journals Precession drift reversal and rapid transport of trapped energetic particles due to an energetic particle driven instability in the Large Helical Device

2021 ◽  
Vol 28 (8) ◽  
pp. 080701
Author(s):  
M. Idouakass ◽  
Y. Todo ◽  
H. Wang ◽  
J. Wang ◽  
R. Seki ◽  
...  
Keyword(s):  
Energetic Particle ◽  
Energetic Particles ◽  
Rapid Transport

Study on the variation of energetic particle pitch angle caused by NWC VLF transmitter

2020 ◽  
Author(s):  
Wei Chu ◽  
Song Xu ◽  
ZhenXia Zhang ◽  
Jianping Huang ◽  
Zhima Zeren ◽  
...  
Keyword(s):  
Pitch Angle ◽  
Energetic Particle ◽  
Electron Flux ◽  
Energetic Electron ◽  
Energetic Particles ◽  
Observation Data ◽  
Electron Loss ◽  
Loss Mechanism ◽  
Central Location ◽  
The North

<p>Based on the observation data collected by the Energetic Particles Detector Package(HEPP) on board CSES satellite during the period of 2018 and 2019.We analyzed the characterizes of pitch angle spectrum of energetic electron precipitated caused by NWC. Our analysis revealed in details the transient properties of the space electrons induced by the man-made VLF wave emitted by the transmitter at NWC.The center location of the NWC electron flux locates in the north hemisphere other than in the south hemisphere during both quiet and disturbance period which is surprising.And the central location of NWC electron belt move westwards during the geomagnetic storm.The pitch angle distributions of the precipitation electron have the maximum flux at about 60-70 degree other than at 90 degree.The pitch angle distributions presented here are examined for evidence of the transportation mechanism especially for the electron loss mechanism.</p><p> </p>

Current sheets, magnetic islands and associated particle acceleration in the solar wind as observed by Ulysses near the ecliptic plane

2020 ◽  
Author(s):  
Olga Malandraki ◽  
Olga Khabarova ◽  
Roberto Bruno ◽  
Gary Zank ◽  
Gang Li and the ISSI-405 team
Keyword(s):  
Solar Wind ◽  
Particle Acceleration ◽  
Magnetic Reconnection ◽  
Energetic Particle ◽  
Particle Flux ◽  
Energetic Particles ◽  
Magnetic Islands ◽  
Intermittent Turbulence ◽  
Current Sheets ◽  
Energetic Particle Flux

<p>Recent studies of particle acceleration in the heliosphere have revealed a new mechanism that can locally energize particles up to several MeV/nuc. Stream-stream interactions as well as the heliospheric current sheet – stream interactions lead to formation of large magnetic cavities, bordered by strong current sheets (CSs), which in turn produce secondary CSs and dynamical small-scale magnetic islands (SMIs) of ~0.01AU or less owing to magnetic reconnection. It has been shown that particle acceleration or re-acceleration occurs via stochastic magnetic reconnection in dynamical SMIs confined inside magnetic cavities observed at 1 AU. The study links the occurrence of CSs and SMIs with characteristics of intermittent turbulence and observations of energetic particles of keV-MeV/nuc energies at ~5.3 AU. We analyze selected samples of different plasmas observed by Ulysses during a widely discussed event, which was characterized by a series of high-speed streams of various origins that interacted beyond the Earth’s orbit in January 2005. The interactions formed complex conglomerates of merged interplanetary coronal mass ejections, stream/corotating interaction regions and magnetic cavities. We study properties of turbulence and associated structures of various scales. We confirm the importance of intermittent turbulence and magnetic reconnection in modulating solar energetic particle flux and even local particle acceleration. Coherent structures, including CSs and SMIs, play a significant role in the development of secondary stochastic particle acceleration, which changes the observed energetic particle flux time-intensity profiles and increases the final energy level to which energetic particles can be accelerated in the solar wind.</p>

Energetic Particle Environment near the Sun from Parker Solar Probe

2020 ◽  
Author(s):  
Nathan Schwadron ◽  
Keyword(s):  
Energetic Particle ◽  
Energetic Particles ◽  
Solar Energetic Particles ◽  
Radiation Environment ◽  
The Sun ◽  
Particle Radiation ◽  
Integrated Science ◽  
Direct Observations ◽  
Interaction Regions ◽  
Inner Heliosphere

<p>NASA’s Parker Solar Probe (PSP) mission recently plunged through the inner heliosphere to perihelia at ~24 million km (~35 solar radii), much closer to the Sun than any prior human made object. Onboard PSP, the Integrated Science Investigation of the Sun (ISʘIS) instrument suite made groundbreaking measurements of solar energetic particles (SEPs). Here we discuss the near-Sun energetic particle radiation environment over PSP’s first two orbits, which reveal where and how energetic particles are energized and transported. We find a great variety of energetic particle events accelerated both locally and remotely. These include co-rotating interaction regions (CIRs), “impulsive” SEP events driven by acceleration near the Sun, and events related to Coronal Mass Ejections (CMEs). These ISʘIS observations made so close to the Sun provide critical information for investigating the near-Sun transport and energization of solar energetic particles that was difficult to resolve from prior observations. We discuss the physics of particle acceleration and transport in the context of various theories and models that have been developed over the past decades. This study marks a major milestone with humanity’s reconnaissance of the near-Sun environment and provides the first direct observations of the energetic particle radiation environment in the region just above the corona.</p>

scholarly journals Climate Impact of Polar Mesospheric and Stratospheric Ozone Losses due to Energetic Particle Precipitation

2017 ◽  
Author(s):  
Katharina Meraner ◽  
Hauke Schmidt
Keyword(s):  
Radiative Forcing ◽  
Energetic Particle ◽  
Climate Model ◽  
Stratospheric Ozone ◽  
Energetic Particles ◽  
Climate Impact ◽  
Particle Precipitation ◽  
Ozone Loss ◽  
Mesospheric Ozone ◽  
Energetic Particle Precipitation

Abstract. Energetic particles enter the polar atmosphere and enhance the production of nitrogen oxides and hydrogen oxides in the winter stratosphere and mesosphere. Both components are powerful ozone destroyers. Recently, it has been inferred from observations that the direct effect of energetic particle precipitation (EPP) causes significant long-term mesospheric ozone variability. Satellites observe a decrease in mesospheric ozone by up to 34 % between EPP maximum and EPP minimum. Here, we analyze the climate impact of polar mesospheric and polar stratospheric ozone losses due to EPP in the coupled climate model MPI-ESM. Using radiative transfer modeling, we find that the radiative forcing of a mesospheric ozone loss during polar night is small. Hence, climate effects of a mesospheric ozone loss due to energetic particles seem unlikely. A stratospheric ozone loss due to energetic particles warms the winter polar stratosphere and subsequently weakens the polar vortex. However, those changes are small, and few statistically significant changes in surface climate are found.

The Energetic Particle Detector (EPD) Electron-Proton Telescope (EPT) on Solar Orbiter: In-flight calibration and background correction of science data.

2021 ◽  
Author(s):  
Daniel Pacheco ◽  
Alexander Kollhoff ◽  
Robert F. Wimmer-Schweingruber ◽  
Johan L. Freiherr von Forstner ◽  
Christoph Terasa ◽  
...  
Keyword(s):  
Energetic Particle ◽  
Solar Energetic Particle ◽  
Energetic Particles ◽  
First Year ◽  
Particle Detector ◽  
Science Data ◽  
Directional Information ◽  
Wide Range ◽  
Electrons And Ions ◽  
Complete Set

<p>Solar Orbiter was launched in February 2020 carrying the most complete set of in-situ and remote sensing instruments, for the study of the Sun and the heliosphere. The Energetic Particle Detector (EPD) on board of Solar Orbiter was switched on on 28 February 2020 and, since then, it has provided us with measurements of the energetic particles traveling through the inner heliosphere. The EPD suite is composed of a set of different sensors measuring electrons, protons and ions in a wide range of energies.</p><p>The Electron-Proton Telescope (EPT) was designed to measure electrons and ions with energies of 35-4000keV and 45-7000keV respectively. By utilizing the so-called magnet/foil-technique, EPT is capable of measuring energetic particles with a high temporal and energy resolution while obtaining directional information from its four different fields of view. Although EPT is well suited for the study of solar energetic particle events, instrumental effects such as the contamination of EPT data products by GCR particles need to be understood for a correct interpretation of the data.</p><p>We will present our current understanding of the background and calibration of EPT based on the data gathered during the first year of Solar Orbiter’s mission.</p>

Linear dispersion relation of geodesic acoustic modes driven by trapped and circulating energetic particles

2021 ◽  
Vol 87 (4) ◽  
Author(s):  
I. Chavdarovski ◽  
M. Schneller ◽  
A. Biancalani
Keyword(s):  
Dispersion Relation ◽  
Pitch Angle ◽  
Energetic Particle ◽  
Energetic Particles ◽  
Ion Beams ◽  
Mean Velocity ◽  
Local Dispersion ◽  
Acoustic Modes ◽  
Slowing Down ◽  
Tail Distribution

We derive the local dispersion relation of energetic-particle-induced geodesic acoustic modes (EGAMs) for both trapped and circulating ion beams with single pitch angle slowing-down and Maxwellian distributions, as well as a bump-on-tail distribution in tokamak plasmas. For slowing-down and Maxwellian particles, the solutions of the local dispersion relation give the spectrum, growth rate and thresholds of excitation as functions of the pitch angle, beam density and frequency of the energetic particles bounce motion. For circulating ions there is only one unstable branch with frequency below the GAM continuum and a threshold of excitation in the pitch angle, for both the slowing-down and single pitch Maxwellian distributions. Trapped particles cause no excitation of a mode for neither slowing-down nor Maxwellian ion beams, but they can excite a mode with a bump-on-tail distribution when the mean velocity of the beam is larger than the threshold and the energetic particle bounce frequency is high enough.

scholarly journals Impact of solar versus volcanic activity variations on tropospheric temperatures and precipitation during the Dalton Minimum

2014 ◽  
Vol 10 (3) ◽  
pp. 921-938 ◽  
Author(s):  
J. G. Anet ◽  
S. Muthers ◽  
E. V. Rozanov ◽  
C. C. Raible ◽  
A. Stenke ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
Solar Irradiance ◽  
Energetic Particle ◽  
Volcanic Eruptions ◽  
Energetic Particles ◽  
Hadley Cell ◽  
Particle Spectrum ◽  
Volcanic Aerosol ◽  
Mean Temperature ◽  
Dalton Minimum

Abstract. The aim of this work is to elucidate the impact of changes in solar irradiance and energetic particles versus volcanic eruptions on tropospheric global climate during the Dalton Minimum (DM, AD 1780–1840). Separate variations in the (i) solar irradiance in the UV-C with wavelengths λ < 250 nm, (ii) irradiance at wavelengths λ > 250 nm, (iii) in energetic particle spectrum, and (iv) volcanic aerosol forcing were analyzed separately, and (v) in combination, by means of small ensemble calculations using a coupled atmosphere–ocean chemistry–climate model. Global and hemispheric mean surface temperatures show a significant dependence on solar irradiance at λ > 250 nm. Also, powerful volcanic eruptions in 1809, 1815, 1831 and 1835 significantly decreased global mean temperature by up to 0.5 K for 2–3 years after the eruption. However, while the volcanic effect is clearly discernible in the Southern Hemispheric mean temperature, it is less significant in the Northern Hemisphere, partly because the two largest volcanic eruptions occurred in the SH tropics and during seasons when the aerosols were mainly transported southward, partly because of the higher northern internal variability. In the simulation including all forcings, temperatures are in reasonable agreement with the tree ring-based temperature anomalies of the Northern Hemisphere. Interestingly, the model suggests that solar irradiance changes at λ < 250 nm and in energetic particle spectra have only an insignificant impact on the climate during the Dalton Minimum. This downscales the importance of top–down processes (stemming from changes at λ < 250 nm) relative to bottom–up processes (from λ > 250 nm). Reduction of irradiance at λ > 250 nm leads to a significant (up to 2%) decrease in the ocean heat content (OHC) between 0 and 300 m in depth, whereas the changes in irradiance at λ < 250 nm or in energetic particles have virtually no effect. Also, volcanic aerosol yields a very strong response, reducing the OHC of the upper ocean by up to 1.5%. In the simulation with all forcings, the OHC of the uppermost levels recovers after 8–15 years after volcanic eruption, while the solar signal and the different volcanic eruptions dominate the OHC changes in the deeper ocean and prevent its recovery during the DM. Finally, the simulations suggest that the volcanic eruptions during the DM had a significant impact on the precipitation patterns caused by a widening of the Hadley cell and a shift in the intertropical convergence zone.

scholarly journals Energetic particle investigation using the ERNE instrument

1996 ◽  
Vol 14 (5) ◽  
pp. 497-502 ◽  
Author(s):  
J. Torsti ◽  
E. Valtonen ◽  
L. Kocharov ◽  
M. Lumme ◽  
T. Eronen ◽  
...  
Keyword(s):  
Solar Flares ◽  
Particle Transport ◽  
Energetic Particle ◽  
Interplanetary Space ◽  
Solar Wind Plasma ◽  
Energetic Particles ◽  
Particle Energy ◽  
Particle Properties ◽  
Energetic Particle Transport ◽  
Accelerated Particles

Abstract. During solar flares and coronal mass ejections, nuclei and electrons accelerated to high energies are injected into interplanetary space. These accelerated particles can be detected at the SOHO satellite by the ERNE instrument. From the data produced by the instrument, it is possible to identify the particles and to calculate their energy and direction of propagation. Depending on variable coronal/interplanetary conditions, different kinds of effects on the energetic particle transport can be predicted. The problems of interest include, for example, the effects of particle properties (mass, charge, energy, and propagation direction) on the particle transport, the particle energy changes in the transport process, and the effects the energetic particles have on the solar-wind plasma. The evolution of the distribution function of the energetic particles can be measured with ERNE to a better accuracy than ever before. This gives us the opportunity to contribute significantly to the modeling of interplanetary transport and acceleration. Once the acceleration/transport bias has been removed, the acceleration-site abundance of elements and their isotopes can be studied in detail and compared with spectroscopic observations.

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