Modelling the production of terrestrial gamma-ray flashes during the final leader step

2020 ◽  
Author(s):  
Christoph Köhn ◽  
Olivier Chanrion ◽  
Heumesser Matthias ◽  
Krystallia Dimitriadou ◽  
Torsten Neubert
Keyword(s):  
Electric Fields ◽  
Gamma Ray ◽  
Temporal Evolution ◽  
High Energy ◽  
Monte Carlo Code ◽  
Relative Timing ◽  
Charge Layer ◽  
High Energy Particles ◽  
Electron And Photon

<p>Recent measurements by the Atmosphere-Space Interactions Monitor (ASIM) indicate that the production of energetic electrons and of subsequent terrestrial gamma-ray flashes (TGFs) occurs immediately prior to intracloud lightning breakdown. Inspired by this finding, we relate the production of high-energy particles to the occurrence of streamer coronas initiated during the final leader step when the leader is in the vicinity of the upper cloud charge layer. Therefore, we model the acceleration of electrons and the subsequent production of energetic photons in the electric fields of the two encountering streamer coronas which are initiated in the vicinity of the leader tip and of the charge layer. Applying a particle Monte Carlo code, we first initiate thermal electrons in the electric field of the leader tip and subsequently turn on the streamer coronas and simulate the acceleration of electrons from thermal energies to energies of several tens of MeV. We present the temporal evolution of the electron and photon energies and spectra, and discuss the role of the electric fields of the encountering streamer coronas. Finally, we relate our results to ASIM measurements and discuss the duration and the relative timing of TGF bursts.</p>

scholarly journals Gamma-Ray and Neutrino Signals from Accretion Disk Coronae of Active Galactic Nuclei

Galaxies ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 36
Author(s):  
Yoshiyuki Inoue ◽  
Dmitry Khangulyan ◽  
Akihiro Doi
Keyword(s):  
Active Galactic Nuclei ◽  
Gamma Ray ◽  
Galactic Nuclei ◽  
High Energy ◽  
Thermal Activity ◽  
X Ray ◽  
Cascade Models ◽  
Coronal Activity ◽  
Ngc 1068 ◽  
High Energy Particles

To explain the X-ray spectra of active galactic nuclei (AGN), non-thermal activity in AGN coronae such as pair cascade models has been extensively discussed in the past literature. Although X-ray and gamma-ray observations in the 1990s disfavored such pair cascade models, recent millimeter-wave observations of nearby Seyferts have established the existence of weak non-thermal coronal activity. In addition, the IceCube collaboration reported NGC 1068, a nearby Seyfert, as the hottest spot in their 10 yr survey. These pieces of evidence are enough to investigate the non-thermal perspective of AGN coronae in depth again. This article summarizes our current observational understanding of AGN coronae and describes how AGN coronae generate high-energy particles. We also provide ways to test the AGN corona model with radio, X-ray, MeV gamma ray, and high-energy neutrino observations.

scholarly journals Particle Acceleration in High-Energy Gamma-Ray Sources

1994 ◽  
Vol 142 ◽  
pp. 877-881
Author(s):  
David Eichler
Keyword(s):  
Gamma Rays ◽  
Production Efficiency ◽  
Gamma Ray ◽  
High Energy ◽  
Thick Target ◽  
Shock Acceleration ◽  
High Production Efficiency ◽  
Energy Gamma ◽  
High Production ◽  
High Energy Particles

AbstractMany proficient gamma-ray sources show energy spectra that are consistent with E−2 primary spectra. Such sources include recently identified gamma-ray quasars and some gamma-ray bursts. Assuming thick target conversion, this is consistent with shock acceleration, and the dominance of the gamma rays of the luminosity is also consistent with previous predictions of high production efficiency of fresh cosmic rays in shocks. The spectral cutoffs in the gamma rays may offer clues as to whether the high-energy particles are electrons or protons. Resolution of this matter might have implications for the nature of the sources and for theory of shock accelerated electrons.Subject headings: acceleration of particles — gamma rays: bursts — shock waves

Gamma-Ray Solar Flares and In Situ Particle Acceleration

2017 ◽  
Vol 13 (S335) ◽  
pp. 43-48 ◽  
Author(s):  
Alexei Struminsky
Keyword(s):  
Gamma Ray ◽  
Solar Energetic Particle ◽  
High Energy ◽  
Shock Acceleration ◽  
Relative Role ◽  
Energy Gamma ◽  
Mass Ejection ◽  
Flare Site

AbstractAt present two concurrent paradigms of solar energetic particle (SEP) origin exist: acceleration directly in the flare site or by the shock wave of coronal mass ejection (CME). Active discussions on a relative role of flares and coronal mass ejections for SEP acceleration and propagation are continuous until now. In my opinion only future observations of solar high energy γ–emission with better spectral, spatial and temporal resolution may clarify this issue. In my report I discuss possible signatures of the flare and shock acceleration processes. What is a picture provided by the current instruments? What can we expect to observe with a perfect instrument in high energy gamma rays in one or another case on a time scale of impulsive and long decay flare phases?

scholarly journals Particle Acceleration in Solar Flares and Coronal Mass Ejections

2000 ◽  
Vol 195 ◽  
pp. 15-25
Author(s):  
R. P. Lin
Keyword(s):  
Particle Acceleration ◽  
Energy Release ◽  
Coronal Mass Ejections ◽  
Solar Flares ◽  
Gamma Ray ◽  
Solar Energetic Particle ◽  
High Energy ◽  
Total Rate ◽  
Solar Energetic Particle Events ◽  
High Energy Particles

The Sun accelerates ions up to tens of GeV and electrons up to 100s of MeV in solar flares and coronal mass ejections. The energy in the accelerated tens-of-keV electrons and possibly ~1 MeV ions constitutes a significant fraction of the total energy released in a flare, implying that the particle acceleration and flare energy release mechanisms are intimately related. The total rate of energy release in transients from flares down to microflares/nanoflares may be significant for heating the active solar corona.Shock waves driven by fast CMEs appear to accelerate the high-energy particles in large solar energetic particle events detected at 1 AU. Smaller SEP events are dominated by ~1 to tens-of-keV electrons, with low fluxes of up to a few MeV/nucleon ions, typically enriched in 3He. The acceleration in gamma-ray flares appears to resemble that in these small electron-3He SEP events.

scholarly journals Optical Monitoring of Gamma-Ray Loud Blazars

1996 ◽  
Vol 175 ◽  
pp. 287-288
Author(s):  
C.M. Raiteri ◽  
G. Ghisellini ◽  
M. Villata ◽  
G. DE FRANCESCO ◽  
S. Bosio ◽  
...  
Keyword(s):  
Gamma Ray ◽  
High Energy ◽  
Significant Fraction ◽  
Optical Monitoring ◽  
Inverse Compton ◽  
Theoretical Predictions ◽  
Γ Ray ◽  
Uv Photons ◽  
High Energy Particles ◽  
Crucial Test

The observations by the Compton Gamma Ray Observatory (CGRO) have shown that highly variable and radio-loud quasars emit a significant fraction of their energy in the γ band. According to the Inverse Compton model, the γ-ray emission is due to upscattering of soft (IR-optical-UV) photons by high energy particles. Optical monitoring is thus of great value in providing information on the mechanisms that rule the production of the seed photons for the γ-ray radiation and on the γ-ray emission itself. In particular, detection of variability correlations between optical and γ-ray emissions would be a crucial test for the theoretical predictions.

Future prospects for y-ray astronomy

1981 ◽  
Vol 301 (1462) ◽  
pp. 693-701 ◽  
Keyword(s):  
Gamma Ray ◽  
Dynamic Pressure ◽  
High Energy ◽  
Compact Objects ◽  
Pressure Effects ◽  
Very High Energy ◽  
Order Of Magnitude ◽  
High Energy Particles ◽  
Nuclear Processes ◽  
The Universe

As y-ray astronomy moves from the discovery to the exploratory phase, the promise of y-ray astrophysics noted by theorists in the late 1940s and 1950s is beginning to be realized. In the future, satellites should carry instruments that will have over an order of magnitude greater sensitivity than those flown thus far, and, for at least some portions of the y-ray energy range, these detectors will also have substantially improved energy and angular resolution. The information to be obtained from these experiments should greatly enhance our knowledge of several astrophysical phenomena including the very energetic and nuclear processes associated with compact objects, astrophysical nucleosynthesis, solar particle acceleration, the chemical composition of the planets and other bodies of the Solar System, the structure of our Galaxy, the origin and dynamic pressure effects of the cosmic rays, high energy particles and energetic processes in other galaxies especially active ones, and the degree of matter-antimatter symmetry of the Universe. The y-ray results of the forthcoming programs such as Gamma-I, the Gamma Ray Observatory, the y-ray burst network, Solar Polar, and very high energy y-ray telescopes on the ground will almost certainly provide justification for more sophisticated telescopes. These advanced instruments might be placed on the Space Platform currently under study by N.A.S.A.

Radiation Hard Devices Based on SiC

2006 ◽  
Vol 527-529 ◽  
pp. 1473-1476 ◽  
Author(s):  
Evgenia V. Kalinina ◽  
Anatoly M. Strel'chuk ◽  
Alexander A. Lebedev ◽  
Nikita B. Strokan ◽  
Alexander M. Ivanov ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Signal Amplitude ◽  
High Energy ◽  
Pair Creation ◽  
Transistor Structure ◽  
Electron Hole ◽  
X Ray ◽  
Electron Hole Pair ◽  
Radiation Hard ◽  
High Energy Particles

The effect of irradiation with protons, electrons, neutrons, x-ray radiation and gamma-ray photons as well as with different ions on properties of starting SiC material and devices based on it was studied. The rectifying properties of the diode structures, which degraded as a result of irradiation with high energy particles, were recovered at higher operation temperatures. The transistor structure SiC-based detectors were realized with the signal amplification by a factor of tens under irradiation. The energy resolution of 0.34 %, commensurable with Si-detectors, has been achieved for SiC detectors and is correct for all classes of short range ions. The maximum signal amplitude corresponds, in SiC, to a mean electron-hole pair creation energy of 7.7 eV.

scholarly journals Long-lasting injection of solar energetic electrons into the heliosphere

2018 ◽  
Vol 613 ◽  
pp. A21 ◽  
Author(s):  
N. Dresing ◽  
R. Gómez-Herrero ◽  
B. Heber ◽  
A. Klassen ◽  
M. Temmer ◽  
...  
Keyword(s):  
Energetic Electron ◽  
Solar Energetic Particle ◽  
High Energy ◽  
Interaction Region ◽  
Energetic Electrons ◽  
Coronal Activity ◽  
High Energy Particles ◽  
Electron Event

Context. The main sources of solar energetic particle (SEP) events are solar flares and shocks driven by coronal mass ejections (CMEs). While it is generally accepted that energetic protons can be accelerated by shocks, whether or not these shocks can also efficiently accelerate solar energetic electrons is still debated. In this study we present observations of the extremely widespread SEP event of 26 Dec 2013 To the knowledge of the authors, this is the widest longitudinal SEP distribution ever observed together with unusually long-lasting energetic electron anisotropies at all observer positions. Further striking features of the event are long-lasting SEP intensity increases, two distinct SEP components with the second component mainly consisting of high-energy particles, a complex associated coronal activity including a pronounced signature of a shock in radio type-II observations, and the interaction of two CMEs early in the event. Aims. The observations require a prolonged injection scenario not only for protons but also for electrons. We therefore analyze the data comprehensively to characterize the possible role of the shock for the electron event. Methods. Remote-sensing observations of the complex solar activity are combined with in situ measurements of the particle event. We also apply a graduated cylindrical shell (GCS) model to the coronagraph observations of the two associated CMEs to analyze their interaction. Results. We find that the shock alone is likely not responsible for this extremely wide SEP event. Therefore we propose a scenario of trapped energetic particles inside the CME–CME interaction region which undergo further acceleration due to the shock propagating through this region, stochastic acceleration, or ongoing reconnection processes inside the interaction region. The origin of the second component of the SEP event is likely caused by a sudden opening of the particle trap.

scholarly journals Analytical Model Nonequilibrium Inhomogeneous Plasma of the Heliosphere

2021 ◽  
Author(s):  
Philipp Vysikaylo
Keyword(s):  
Solar Wind ◽  
Electric Fields ◽  
Inhomogeneous Plasma ◽  
Solar Wind Plasma ◽  
High Energy ◽  
Gas Discharge ◽  
The Sun ◽  
Energetic Electrons ◽  
Positively Charged

We prove that a nonequilibrium inhomogeneous giant gas discharge is realized in the heliosphere with huge values of the parameter <i>E</i>/<i>N</i>, which determines the temperature of electrons. This quasi-stationary discharge determines the main parameters of the weak solar wind (SW) in the heliosphere. In connection with the development of space technologies and the human spacewalk, the problem of the nature of the SW is acute. The study of the interference of gravitational and electrical potentials at the Earth's surface began with the work of Hilbert 1600. Such polarization effects – the interference of Coulomb and gravitational forces – have not been studied well enough even in the heliosphere. Our article is devoted to this problem. Pannekoek-Rosseland-Eddington model do not take into account the important role of highly energetic running (away from the Sun) electrons and, accordingly, the duality of electron fluxes. According to an alternative model formulated by we, highly energetic (escaping from the Sun) electrons leave the Sun and the heliosphere, and weakly energetic ones, unable to leave the Coulomb potential well (hole) – the positively charged Sun and the heliosphere, return to the Sun. The weak difference between the opposite currents of highly energetic (escaping from the Sun) electrons and weakly energetic (returning to the Sun) electrons is compensated by the current of positive ions and protons from the Sun – SW. These dynamic processes maintain a quasi-constant effective dynamic charge of the Sun and the entire heliosphere. At the same time, quasi-neutrality in the Sun and heliosphere is well performed up to 10<sup>-36</sup>. According to experiments and analytical calculations based on our model: 1) the plasma in the corona is nonequilibrium; 2) the maximum electron temperature is T<sub>e</sub> ~ 1-2 million degrees; 3) T<sub>e</sub> grows from 1000 km away from the Sun and 4) the role of highly energetic electrons escaping from the plasma leads to a significant increase in the effective: solar charge and electric fields in the heliosphere in relation to the Pannekoek-Rosseland-Eddington model. This is due to the absence of a compensation layer that screens the effective charge of the Sun. It is not formed at all due to the escape of highly energetic electrons (as in a conventional gas discharge) in the entire heliosphere with high temperatures exceeding the temperature of the Sun's surface. Thus, the process of escape of highly energetic electrons forms the internal EMF of the entire heliosphere. Interference of gravitational and Coulomb potentials in the entire heliosphere is considered, it is being manifested in generation of two opposite flows of particles: 1) that are neutral or with a small charge (to the Sun), and 2) in the form of high-energy electrons (escaping from the positively charged Sun) and a solar wind (from the Sun). Calculated values of the registered ion parameters in the solar wind were compared with experimental observations. Reasons for generating the ring current in inhomogeneous heliosphere and inapplicability of the Debye theory in describing processes in the solar wind (plasma with current) are considered.

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