Astronomy and Astrophysics – Astronomy
Scientific paper
Jan 1993
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1993aas...18111612c&link_type=abstract
American Astronomical Society, 181st AAS Meeting, #116.12; Bulletin of the American Astronomical Society, Vol. 25, p.735
Astronomy and Astrophysics
Astronomy
Scientific paper
We have investigated the refractive and diffractive properties of one-dimensional interstellar Gaussian plasma lenses at radio frequencies. The physical parameters of the lens system have been combined as much as possible into dimensionless quantities so that entire families of lenses can be studied for each numerical simulation that is performed. For an infinitely distant radio source which is imaged by a plasma lens with an electron column density profile N(x) = N_0 e(-(x/a)(2)) , we find that refractive effects are completely characterized by the dimensionless parameter alpha equiv lambda (2) r_e N_0 D / pi a(2) , where lambda is the wavelength of observation, r_e is the classical electron radius, and D is the separation between observer and lens. The diffractive properties of the lens are completely specified by two parameters: alpha , and the quantity phi_0 = lambda r_e N_0, which is the maximum phase perturbation induced by the lens. For radio sources of finite distance, the parameter alpha is modified by a term involving f, the fractional distance of the lens along the observer-source line of sight. The effects of the plasma lens that have been studied include: (1) modulations in the broadband light curve of the background source as relative transverse motion between source, lens, and observer carries the observer through various focusing and defocusing regions of the lens; (2) image wander, caused by refractive (large scale) perturbations induced on the wave front by the lens; (3) image distortions produced by various optical aberrations inherent in the Gaussian lens; and (4) ray crossing and multiple imaging produced by lenses with large alpha values. We will present the results of these simulations and discuss their application to the wide variety of strong refraction phenomena that have been previously observed, including extreme scattering events of extragalactic sources (Fiedler et al. 1987, Nature, 326, 675) and multiple imaging of pulsar emission (Cordes et al. 1986, ApJ, 310, 737).
Clegg Andrew W.
Fiedler Ralph L.
No associations
LandOfFree
The Gaussian Plasma Lens in Astrophysics does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The Gaussian Plasma Lens in Astrophysics, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Gaussian Plasma Lens in Astrophysics will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1772417