Observations on the Effect of Surface Conditions on Langmuir Probes

Bunting, W. D.; Heikkila, W. J.

doi:10.1063/1.1659208

Cited by 22 publications

(8 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The parameters to be used for obtaining G are a/L•and xl = -eVa/XTe; the surface antenna dc potential is V a = V• + E (V• is the measured rocket floating potential and E the applied bias) if surface effects are neglected. In fact, the value V a "seen" by the plasma is slightly different [see, for instance, Bunting and Heikkila, 1970]. In our case the corresponding difference ( V a becomes less negative) is expected to be rather important [ Vernet, 1973]; this, including the uncertainty on the measured T e, gives the minimum value of the xl range in Table 2.…”

Section: Introductionmentioning

confidence: 66%

The impedance of a dipole antenna in the ionosphere: 2. Comparison with theory

Meyer¹,

Vernet²

1975

Radio Science

View full text Add to dashboard Cite

The interpretation of the experiment EIDI I, described in a companion paper, is undertaken. A relatively complete calculation of the impedance is done including the effect of the temperature of the plasma by using the Vlasov equation and hydrodynamic equations, the structure of the sheath using a simple model of it, the collision frequency computed for an equilibrium plasma, and an estimation of various other small effects (wake, ionospheric gradient, motion of ions, …). The result so obtained is in very good agreement with the experiment for the most part but a strong discrepancy appears in the resistance when X > 1. This indicates that the main features of the theory are correct except that a loss mechanism is missing; some hypothetical ones are discussed.

show abstract

Section: Introductionmentioning

confidence: 66%

The impedance of a dipole antenna in the ionosphere: 2. Comparison with theory

Meyer¹,

Vernet²

1975

Radio Science

View full text Add to dashboard Cite

show abstract

“…In a low-temperature plasma, changes in surface work function potential compete with electronics-imposed voltage changes on the probe. Hysteresis effects occur in the voltage-current characteristic, as the surface properties change in response to different plasma fluxes in a given sweep [Bunting and Heikkila, 1970;Szuszczewicz and Holmes, 1975;Holmes and Szuszczewicz, 1975]. New techniques are being used which involve only short periods of time for deviation of the probe potential from some fixed value.…”

Section: In $Itu Probesmentioning

confidence: 99%

Ionospheric irregularities

Fejer¹,

Kelley²

1980

Reviews of Geophysics

884

644

View full text Add to dashboard Cite

Extensive experimental and theoretical research has been performed in the last decade to study ionospheric irregularities. These studies have shown that plasma instabilities play a major role in the generation of the irregularities. In this work we describe in detail the recent experimental studies of the E and F region irregularities and also the extensive work on plasma instability theories developed to explain them. We also describe both radio wave and spacecraft‐borne experimental techniques to allow a common ground for the understanding of the data from ground‐based and in situ experiments. To date, theoretical work has been mostly concentrated on the low‐latitude irregularities and, together with computer simulations, has been able to explain many aspects of the experimental data. These theoretical efforts are also discussed in some detail. The role of neutral winds in the creation of large‐scale ionospheric structures such as mid‐latitude sporadic E is beyond the scope of this review.

show abstract

“…The results of the numerical calculations will be presented later in section 4. A kinetic theory model of the plasma has been used by Buckley [1966Buckley [ , 1967 The floating potentials of two probes which had been cleaned by ion bombardment were found to be nearly equal [Bunting and Heikkila, 1970], and a separate probe could therefore be used as a reference. Figure 2 shows a servoloop.…”

Section: + Jw4•eor•k 1 --•(1 + •P•)-• (12) Whero M = R•/ad the Ratiomentioning

confidence: 99%

The Impedance Characteristic of a Spherical Probe in an Isotropic Plasma

Tarstrup¹,

Heikkila²

1972

Radio Science

Self Cite

View full text Add to dashboard Cite

An experimental investigation of the impedance characteristic of a spherical plasma probe has been carried out for a quantitative assessment of theoretical work, and of hydrodynamic or fluid theory in particular. A stable, low temperature (T ~ 500øK) plasma was produced in nitrogen by a cold cathode discharge, with a plasma frequency of the order of 15 MHz and with an electron collision frequency in the range of 100 to 107 sec-•. The probe consisted of two hemispheres, one serving as a guard to eliminate the effects of the, connecting leads; this geometry provided an almost purely radial electric field over the test hemisphere. Probe diameters ranged from 7 to 20 mm ( 10 to 30 Debye lengths). Hydrodynamic probe theory was tested against the experimental results for the specific cases corresponding to the probe at floating potential and at space potential. Good agreement was obtained for both the real and imaginary parts. The real part of the impedance shows a peak near the plasma frequency, a small shift being explicable in terms of realistic sheath profiles. Electron density can thus be deduced rather accurately, and electron temperature approximately, on the basis of hydrodynamic theory. Accurate values of the electron-neutral collision frequency were also obtained for plasmas where the collision frequency was larger than 0.4 times the radian plasma frequency. At lower pressures the presence of collisionless or Landau damping was clearly established, and the more accurate kinetic theory is necessary to explain the experimental results. 493 494 TARSTRUP AND HEIKKILA SPHERICAL PROBE IMPEDANCE 495

show abstract

Observations on the Effect of Surface Conditions on Langmuir Probes

Cited by 22 publications

References 1 publication

The impedance of a dipole antenna in the ionosphere: 2. Comparison with theory

The impedance of a dipole antenna in the ionosphere: 2. Comparison with theory

Ionospheric irregularities

The Impedance Characteristic of a Spherical Probe in an Isotropic Plasma

Contact Info

Product

Resources

About