They are trapped using magnetic fields or optical dipole potentials in ultrahigh vacuum chambers. Ionization gauges are used in ultrahigh vacuum. Impact metamorphism is, therefore, characterized by ultrahigh pressure conditions and low temperature. For typical tube dimensions, this occurs only in high or ultrahigh vacuum. However, field emitters work best in conditions of good ultrahigh vacuum. TADIL-A can be used on either high frequency (HF) or ultrahigh frequency (UHF). The WSF thus created an ultrahigh vacuum in its wake. The Mamyshev regenerator can handle return-to-zero signals with ultrahigh data bit rates.