Langmuir waves close to the Sun have been observed with greater energy electrons and Langmuir waves further away from the Sun show up with lower energy electrons. The accelerated electron beam is injected in the solar corona at 0.014 solar radii. We find that the maximum electron speed X growing Langmuir waves increases and peaks at 0.38 c at 5 solar radii, and consequently decreases as r-0.5 to 0.17 c at 50 solar radii for a beam with nbeam = 107 cm-3 and spectral index a = 8. We likewise find that at 13 solar radii, high energy electrons (60 keV) propagate scatter complimentary, whilst low energy (10 keV) electron show up earlier than anticipated with the electron distribution function experiencing diffusion in time, for the very same nbeam-a set. The associated simulated type III solar radio burst supplies us with the velocity variety of electron velocities of its moms and dad electron beam that can connect resonantly with the background plasma of the inner heliosphere.
Figure 2. Optimum electron speed growing Langmuir waves X for various values of a (leading) and nbeam (bottom) between 0 and 5 solar radii. (from Lorfing and Reid, 2023).
We differ two initial beam specifications, the initial beam density nbeam and the speed spectral index a to analyse their result on the energy variety of electrons resonantly engaging with the plasma of the inner heliosphere. The quantity of Langmuir waves being produced at each range is dependent on our option of preliminary beam parameters that themselves control the initial beam density U. And increase in U makes the greater energy electrons more unstable to Langmuir wave development, resulting in more Langmuir waves being produced. U depends on the electron density, and reduces as a function of distance. We observe concurring outcomes with greater values of a (more low energy electrons than high energy ones) causing a lower X, and vice versa, however an overall decrease in X with distance (Figure 2, left). A higher initial beam density is associated with more electrons at all speeds being injected when we vary the initial beam density nbeam. This leads to a higher X for a greater nbeam and vice versa (Figure 2, right).
Conclusions.
We likewise discover that at 13 solar radii, high energy electrons (60 keV) propagate scatter complimentary, whilst low energy (10 keV) electron arrive earlier than anticipated with the electron distribution function experiencing diffusion in time, for the exact same nbeam-a set. The associated simulated type III solar radio burst provides us with the speed variety of electron velocities of its parent electron beam that can communicate resonantly with the background plasma of the inner heliosphere.
Based on a recent paper by C. Y. Lorfing and H. A. S. Reid, 2023, Sol. Phys., DOI: https://doi.org/10.1007/s11207-023-02145-2.
References.
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Ginzburg, V. L. and Zhelezniakov, V. V.: 1958, Sov. Ast. Vol. 2.
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Reid, H. A. S. and Kontar, E. P.: 2013, Sol. Phys., 285, 217-232.
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Solar sped up electron beams communicate with the background plasma of the solar wind to locally produce Langmuir waves and consequently produce radio emission (Ginzburg and Zhelezniakov 1958).
Numerous observations at different distances from the Sun by spacecrafts like Solar Orbiter (0.5 AU) and ACE (1AU) reveal different energy series of electrons engaging with the plasma to produce Langmuir oscillations. At 0.5 AU, non-thermal electrons in the deca-keV range arrive co-temporal to the Langmuir oscillations (Gomez-Herrero et al, 2021). At 1AU, there are no associated plasma waves observed the exact same energy electrons propagate scatter totally free, and (Dröge and Kartavykh, 2009). Langmuir waves close to the Sun have actually been observed with higher energy electrons and Langmuir waves farther away from the Sun show up with lower energy electrons. This shows that there is a limit in the energy variety of electrons for resonant wave-particle interactions, extremely based on distance, that needs to be investigated further.
Numerical research studies of electron beam characteristics as they travel through the solar plasma show that the kinetic homes of these beams depend extremely on the preliminary electron beam specifications like the electron density and the electron energy circulation (Li and Cairns, 2013a, Reid and Kontar 2018).
Optimum electron velocity growing Langmuir waves, X.
X peaks at solar radii at 0.38 c. In red is a healthy proving X reduces as r-0.5 over the optimum velocity data in blue. (from Lorfing and Reid, 2023).
We replicate the injection of an electron beam in the solar corona and the subsequent proliferation out into interplanetary area. Wave-particle interactions are simulated using a quasilinear approach to kinetic theory, penetrating which electron velocities grow the most Langmuir waves at various distances from the Sun. The accelerated electron beam is injected in the solar corona at 0.014 solar radii. We calculate the maximum electron speed growing Langmuir waves X at each point in range from the injection site (0.014 solar radii) out to 50 solar radii (Figure 1). This is done by determining the highest speed where df/dv > > 0 in the electron distribution function at each moment. X at first increases to 0.38 c at 5 solar radii and after that decrease roughly as r-0.5 to 0.17 c at 50 solar radii. At the same time, the amount of Langmuir waves grown above thermal level by the beam reduces from 6 × 104 at 13 solar radii to 8 × 103 at 33 solar radii.
Simulation work of beam-plasma interactions has actually revealed that the speed dependency of the electron distribution function follows an unfavorable power law (Reid and Kontar 2018)
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Velocity spectral index a and initial beam density nbeam.
