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We present high-pass filtered continuum images of the inner$3.5^\circ\times2.5^\circ$ of the Galactic center at 20 cm with $6.4''$resolution. These mosaic images are taken with MeerKAT and reveal a largenumber of narrow filaments, roughly an order of magnitude increase in theirnumbers compared to past measurements. For the first time, we carry outpopulation studies of the spectral index and magnetic field of the entireregion. The mean spectral indices of the filaments are steeper than supernovaremnants (SNRs) (-0.62) with a value of $\alpha\sim-0.83$. The variation in$\alpha$ is much larger than for the SNRs, suggesting that thesecharacteristics have a different origin. A large-scale cosmic-ray driven windhas recently been proposed to explain the origin of filaments and thelarge-scale 430 pc bipolar radio and X-ray structure. This favors thepossibility that the large-scale bipolar radio/X-ray structure is produced bypast activity of Sgr A* rather than coordinated burst of supernovae. A trend ofsteeper indices is also noted with increasing distance from the Galactic plane.This could be explained either by synchrotron cooling or weak shocksaccelerating cosmic-ray particles in the context of the cosmic-ray driven wind.The mean magnetic field strengths along the filaments ranges from $\sim100$ to400 $\mu$G depending on the assumed ratio of cosmic-ray protons to electrons.Given that there is a high cosmic ray pressure in the Galactic center, thelarge equipartition magnetic field implies that the magnetic field is weak inmost of the interstellar volume of the Galactic center.

Statistical Properties of the Population of the Galactic Center Filaments: The Spectral Index and Equipartition Magnetic Field