scholarly journals Parker Solar Probe Evidence for the Absence of Whistlers Close to the Sun to Scatter Strahl and to Regulate Heat Flux

2022 ◽  
Vol 924 (2) ◽  
pp. L33
Author(s):  
C. Cattell ◽  
A. Breneman ◽  
J. Dombeck ◽  
E. Hanson ◽  
M. Johnson ◽  
...  
Keyword(s):  
Heat Flux ◽  
Electric Field ◽  
Acoustic Waves ◽  
Electron Distribution Function ◽  
The Sun ◽  
Temperature Anisotropy ◽  
Ion Acoustic Waves ◽  
Plasma Properties ◽  
Electron Distributions ◽  
Whistler Mode Waves

Abstract Using the Parker Solar Probe FIELDS bandpass-filter data and SWEAP electron data from Encounters 1 through 9, we show statistical properties of narrowband whistlers from ∼16 R s to ∼130 R s, and compare wave occurrence to electron properties including beta, temperature anisotropy, and heat flux. Whistlers are very rarely observed inside ∼28 R s (∼0.13 au). Outside 28 R s, they occur within a narrow range of parallel electron beta from ∼1 to 10, and with a beta-heat flux occurrence consistent with the whistler heat flux fan instability. Because electron distributions inside ∼30 R s display signatures of the ambipolar electric field, the lack of whistlers suggests that the modification of the electron distribution function associated with the ambipolar electric field or changes in other plasma properties must result in lower instability limits for the other modes (including the observed solitary waves and ion acoustic waves) that are observed close to the Sun. The lack of narrowband whistler-mode waves close to the Sun and in regions of either low (<0.1) or high (>10) beta is also significant for the understanding and modeling of the evolution of flare-accelerated electrons and the regulation of heat flux in astrophysical settings including other stellar winds, the interstellar medium, accretion disks, and the intragalaxy cluster medium.

Experimental evidence of the effect of heat flux on Thomson scattering off ion acoustic waves

2000 ◽  
Vol 61 (2) ◽  
pp. 1949-1953 ◽  
Author(s):  
F. Amiranoff ◽  
S. D. Baton ◽  
S. Hüller ◽  
V. Malka ◽  
A. Modena ◽  
...  
Keyword(s):  
Heat Flux ◽  
Experimental Evidence ◽  
Acoustic Waves ◽  
Thomson Scattering ◽  
Ion Acoustic Waves ◽  
Ion Acoustic

scholarly journals Fokker-Planck simulations of ultrashort-pulse laser-plasma interactions

1992 ◽  
Vol 10 (3) ◽  
pp. 461-471 ◽  
Author(s):  
L. Drska ◽  
J. Limpouch ◽  
R. Liska
Keyword(s):  
Heat Flux ◽  
Distribution Function ◽  
Laser Radiation ◽  
Electric Field ◽  
Electron Distribution ◽  
Electron Distribution Function ◽  
Laser Pulses ◽  
Ultrashort Laser Pulses ◽  
Ultrashort Pulse Laser ◽  
The Impact

The interaction of ultrashort laser pulses with a fully ionized plasma is investigated in the plane geometry by means of numerical simulation. The impact of the space oscillations in the amplitude of the laser electric field on the shape of the electron distribution function, on laser beam absorption, and on electron heat transport is demonstrated. Oscillations in the absorption rate of laser radiation with the minima coincident to the maxima of the laser electric field lead to a further decrease in the absorption of laser radiation. Heat flux in the direction of increasing temperature in the underdense region is caused by the modification of the electron distribution function and by the density gradient. A limitation of heat flux to the overdense plasma isobserved with the flux limiter in range 0.03–0.08, growing moderately with the intensity 1014–1016 W/cm2 of the incident 1.2-ps laser pulse.

scholarly journals Cluster observations and theoretical identification of broadband waves in the auroral region

2005 ◽  
Vol 23 (12) ◽  
pp. 3739-3752 ◽  
Author(s):  
M. Backrud-Ivgren ◽  
G. Stenberg ◽  
M. André ◽  
M. Morooka ◽  
Y. Hobara ◽  
...  
Keyword(s):  
Electric Field ◽  
Acoustic Waves ◽  
Auroral Region ◽  
Parallel Electric Field ◽  
Ion Acoustic Waves ◽  
Ion Cyclotron Waves ◽  
Linear Waves ◽  
Field Lines ◽  
Broadband Waves ◽  
The Waves

Abstract. Broadband waves are common on auroral field lines. We use two different methods to study the polarization of the waves at 10 to 180 Hz observed by the Cluster spacecraft at altitudes of about 4 Earth radii in the nightside auroral region. Observations of electric and magnetic wave fields, together with electron and ion data, are used as input to the methods. We find that much of the wave emissions are consistent with linear waves in homogeneous plasma. Observed waves with a large electric field perpendicular to the geomagnetic field are more common (electrostatic ion cyclotron waves), while ion acoustic waves with a large parallel electric field appear in smaller regions without suprathermal (tens of eV) plasma. The regions void of suprathermal plasma are interpreted as parallel potential drops of a few hundred volts.

The Effect of Decreasing Reflection Coefficient of Ion Acoustic Waves Using an Altemative Electric Field

1982 ◽  
Vol 10 (2) ◽  
pp. 135-136 ◽  
Author(s):  
E. M. Barkhudarov ◽  
A. Sh. Dzagnidze ◽  
V. F. Ligin ◽  
D. D. Tskhakaya
Keyword(s):  
Reflection Coefficient ◽  
Electric Field ◽  
Acoustic Waves ◽  
Ion Acoustic Waves ◽  
Ion Acoustic

scholarly journals Evidence for the interplanetary electric potential? WIND observations of electrostatic fluctuations

2002 ◽  
Vol 20 (5) ◽  
pp. 609-618 ◽  
Author(s):  
C. Lacombe ◽  
C. Salem ◽  
A. Mangeney ◽  
D. Hubert ◽  
C. Perche ◽  
...  
Keyword(s):  
Solar Wind ◽  
Electrostatic Field ◽  
Acoustic Waves ◽  
Double Layers ◽  
The Sun ◽  
Ion Acoustic Waves ◽  
The Earth ◽  
Ion Acoustic ◽  
Electrostatic Fluctuations ◽  
Two Fluid

Abstract. In the solar wind at 1 AU, coherent electrostatic waveforms in the ion acoustic frequency range (~ 1 kHz) have been observed by the Time Domain Sampler (TDS) instrument on the Wind spacecraft. Small drops of electrostatic potential (Df > 10-3 V) have been found across some of these waveforms, which can thus be considered as weak double layers (Mangeney et al., 1999). The rate of occurrence of these potential drops, at 1 AU, is estimated by a comparison of the TDS data with simultaneous data of another Wind instrument, the Thermal Noise Receiver (TNR), which measures continuously the thermal and non-thermal electric spectra above 4 kHz. We assume that the potential drops have a constant amplitude and a constant rate of occurrence between the Sun and the Earth. The total potential drop between the Sun and the Earth, which results from a succession of small potential drops during the Sun-Earth travel time, is then found to be about 300 V to 1000 V, of the same order of magnitude as the interplanetary potential implied by a two-fluid or an exospheric model of the solar wind: the interplanetary potential may manifest itself as a succession of weak double layers. We also find that the hourly average of the energy of the non-thermal ion acoustic waves, observed on TNR between 4 and 6 kHz, is correlated to the interplanetary electrostatic field, parallel to the spiral magnetic field, calculated with a two-fluid model: this is another evidence of a relation between the interplanetary electrostatic field and the electrostatic fluctuations in the ion acoustic range. We have yet to discuss the role of the Doppler effect, which is strong for ion acoustic waves in the solar wind, and which can bias the measure of the ion acoustic wave energy in the narrow band 4–6 kHz.Key words. Interplanetary physics (plasma waves and turbulence; solar wind plasma) Space plasma physics (electro-static structures)

Unified theory of whistler mode instability in the presence of a parallel electric field

1984 ◽  
Vol 31 (2) ◽  
pp. 263-274
Author(s):  
Indra Mohan Lal Das ◽  
R. P. Singh
Keyword(s):  
Electric Field ◽  
Full Range ◽  
Present Theory ◽  
Parallel Electric Field ◽  
Temperature Anisotropy ◽  
Whistler Mode ◽  
Plasma Injection ◽  
Whistler Mode Waves ◽  
Particle Pressure ◽  
Analytical Expressions

The propagation characteristics of right-hand circularly polarized whistler mode waves propagating parallel to the external magnetic field in an anisotropic plasma have been reformulated including the effect of a parallel electric field. Analytical expressions for the real frequency and growth rate have been obtained for the full range of the parameters β (the ratio of particle pressure to magnetic pressure of the hot particles), A (temperature anisotropy) and P ( = βA(A + 1)2) without any restriction on the magnitude of the imaginary part of the wave frequency. The effect of cold plasma injection on the marginal instability has also been studied. Possible application of the present theory to the atmospheres of Earth and Jupiter has been discussed.

Influence of High Frequency Electric Field on the Dispersion of Ion-Acoustic Waves in Plasma

1981 ◽  
Vol 36 (1) ◽  
pp. 17-22
Author(s):  
A. Turky ◽  
M. Čerček ◽  
R. Tavzes J. Stefan
Keyword(s):  
Electric Field ◽  
Acoustic Waves ◽  
High Frequency ◽  
Wave Dispersion ◽  
Plasma Stream ◽  
Ion Acoustic Waves ◽  
Ion Acoustic Wave ◽  
High Frequency Electric Field ◽  
Ion Acoustic ◽  
Frequency Electric Field

The modification of the ion-acoustic wave dispersion under the action of a high frequency electric field was studied experimentally, the wave propagating along and against the plasma stream. The frequency of the field amounted to approximately half the electron plasma frequency. It was found that the phase velocity of the ion wave and the plasma drift velocity decrease as the effective high frequency field power increases

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