Minimal Spectrum of LongWave Perturbations: Is Linear Growth Correct Only in the Nonlinear Regime?
Abstract
Very high resolution twodimensional simulations are used to test the generation and growth of the socalled 'minimal' k exp 4 power spectrum which develops from initial conditions which have power only on small scales, such as might result from some process in the early universe. It is confirmed that the amplitude of minimal longwave power grows proportionally to a exp 4, not asquared, where a is the scale factor of the expanding universe. It reverts to asquared only after the shortwave modes are effectively saturated, and by that time an effective longwave power law closer to kcubed is found. Smallscale perturbations may result in much more longwave power than has been generally assumed.
 Publication:

The Astrophysical Journal
 Pub Date:
 December 1990
 DOI:
 10.1086/169420
 Bibcode:
 1990ApJ...364..396S
 Keywords:

 Galactic Clusters;
 Gravitational Fields;
 Long Wave Radiation;
 Nonlinear Systems;
 Computerized Simulation;
 Cosmology;
 High Resolution;
 Power Spectra;
 Astrophysics;
 COSMOLOGY;
 GALAXIES: CLUSTERING;
 GRAVITATION