Magnetic bright points on the solar photosphere, visible in both continuum and G-band images, indicate footpoints of kilogauss magnetic flux tubes extending to the corona. The power spectrum of transverse bright point motion is thus also the power spectrum of Alfven wave excitation, with these waves transporting energy up flux tubes into the corona. This spectrum is a key input in coronal and heliospheric models. After briefly reviewing observations of bright point motion, we present a power spectrum of bright point motion derived from radiative MHD simulations, exploiting spatial resolution higher than can be obtained in observations while using automated tracking to produce large data quantities. We find slightly higher amounts of power at all frequencies compared to observational spectra while confirming the spectrum shape of recent observations. This provides a prediction for DKIST observations of bright points, which will achieve similar resolution. We also present results from tracing test particles in the horizontal plasma flow, finding similar power spectra but differing motion paths. Finally, we introduce a simplified, laminar model of granulation, with which we explore the roles of turbulence and of the properties of the granulation pattern in determining bright point motion.
Solar Heliospheric and INterplanetary Environment (SHINE 2017)
- Pub Date:
- July 2017