Ultrastrong Field Ionization of Ne{sup n+} (n{<=}8): Rescattering and the Role of the Magnetic Field

Ne{sup +} to Ne{sup 8+} ionization yields in 10{sup 14} W/cm{sup 2} to 10{sup 18} W/cm{sup 2} laser fields are reported over a 10{sup 9} dynamic range. A 3D relativistic rescattering model incorporating (e,2e) and (e,3e) electron impact ionization, single- and double-excitation is compared to the data. For double ionization the agreement is excellent; however, for higher charge states the model accounts for only 15% of multielectron nonsequential ionization. Rescattering is not affected by the laser magnetic field until 10{sup 17} W/cm{sup 2}.