Studies on ionization phenomena associated with solid propellant rockets

Capener, E. L.; Chown, J. B.; Dickinson, L. A.

doi:10.2514/6.1965-182

Cited by 6 publications

(1 citation statement)

References 1 publication

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“…Solid propellant grains contain low-ionization-energy elements such as sodium and potassium as impurities, which contribute significantly toward high-density plasma generation. 7,8 However, although exhaust plumes indisputably block launch vehicle telecommunications, satisfactory estimates of the attenuation level have never been established. Unfortunately, only a small number of relevant processes have been modeled so far for the following reasons: (1) The plume plasma that affects RF transmission undergoes non-equilibrium ionization processes, which are affected by alkali metal impurities and E α RF-plume interaction (2) During a rocket flight, RF signals are not only propagated through the plasma plume but are also diffracted and reflected.…”

Section: Introductionmentioning

confidence: 99%

Prediction of In-flight Radio Frequency Attenuation by a Rocket Plume by Applying CFD/FDTD Coupling

Kinefuchi

Okita

Funaki

et al. 2013

49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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During rocket flights, ionized exhaust plumes from solid rocket motors may interfere with radio frequency (RF) transmission under certain conditions. To clarify the physical process involved and to establish the estimation methodology, a plume-RF interference experiment during a sea-level static firing test of a full-scale solid rocket motor was conducted. The result of the ground experiment was adequately matched by a computational fluid dynamics (CFD) model of the plume flow field coupled to a finite-difference timedomain (FDTD) model of RF transmission. The CFD/FDTD coupling method was then refined for predicting interference and RF attenuation levels during an actual rocket flight. The calculated far-field received levels were compared with the in-flight attenuation data at different look angles (angles between the vehicle axis and the line-of-sight of the antennas). The calculated results showed good agreement with the flight data over a wide range of look angles. An adaptation of the model, based on the diffraction theory, proved appropriate both for rough estimation of attenuation and for conducting a preliminary analysis of signal/rocket plume interactions. Nomenclature A = pre-exponential factor for Arrhenius expression, consistent unit c = speed of light, m/s d = width of plasma slab, m e = elementary charge, C E = electric field vector, V/m E a = activation energy for Arrhenius expression, J/mol E y = y-component of electric field, V/m H = magnetic field vector, V/m k = rate coefficient, (m 3 /mol) N−1 /s k B = Boltzmann constant, J/K m e = electron mass, kg n = time step for FDTD method N = reaction order N h = heavy-particle number density, m −3 2 N e = electron number density, m −3 P c = combustion chamber pressure, Pa Q e = electron collision cross section, m 2 R = universal gas constant, J/K/mol T = flow temperature, K T e = electron temperature, K V = received radio wave voltage with motor plume, V V 0 = received radio wave voltage without motor plume, V α = look angle of launch vehicle, deg (shown in Fig. 1) β = roll angle of launch vehicle, deg (shown in Fig. B1) χ = index of attenuation χ 0 = relative electric susceptibility ∆t = time step used in FDTD method, s ∆x, ∆y, ∆z = grid sizes in x, y and z directions, respectively, used in FDTD method, m Φ Φ Φ Φ = recursive accumulator, C/m 2 ε = relative permittivity of free electron ε 0 = vacuum permittivity, F/m η = temperature exponent for Arrhenius expression ϕ c = critical angle, rad λ = radio wave wavelength, m µ = index of refraction ν e = electron collision frequency, s −1 ω = radio wave angular frequency, s −1 ω p = electron plasma frequency, s −1

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Section: Introductionmentioning

confidence: 99%

Prediction of In-flight Radio Frequency Attenuation by a Rocket Plume by Applying CFD/FDTD Coupling

Kinefuchi

Okita

Funaki

et al. 2013

49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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Rocket Exhaust Scattering Effects on Incident Microwave Propagation Characteristics

Rashad

1966

IEEE Trans. Aerosp. Electron. Syst.

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This paper considers the effect of the rocket exhaust turbulence and scattering within the surrounding medium upon the propagation characteristics of incident electromagnetic waves. The exhaust is represented by a cylindrical plasma beam, diffusing through the surrounding medium. The equations of propagation of EM waves are derived for both TE and TM modes. By using a quasi-linear perturbation technique the exhaust is further separated into an inner homogeneous cylindrical plasma beam, and an outer conical inhomogeneous turbulent region. The isotropic change in the temperature of the outer region and its effects on the fluctuations in the density of electrons, collision frequency, and plasma index of refraction are analyzed in detail. It is found that the exhaust turbulence and scattering effects produce linear fluctuations in the E and H fields computed from the exhaust inner region effect. The equations of this paper can be used in the prediction of the radar cross sections and the attenuation of microwaves by rocket exhaust plumes.

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Electrostatic Potential Generated by Rockets on Vehicles in Space

Aronowitz

1968

IEEE Trans. Electromagn. Compat.

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Studies on ionization phenomena associated with solid propellant rockets

Cited by 6 publications

References 1 publication

Prediction of In-flight Radio Frequency Attenuation by a Rocket Plume by Applying CFD/FDTD Coupling

Prediction of In-flight Radio Frequency Attenuation by a Rocket Plume by Applying CFD/FDTD Coupling

Rocket Exhaust Scattering Effects on Incident Microwave Propagation Characteristics

Electrostatic Potential Generated by Rockets on Vehicles in Space

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