Desert Division, while California North and California South make up the California Division.

The National League is an extension of the highly successful US Youth Soccer Regional Leagues (Region I Premier League, Region II Midwest Regional League, Region III Southern Premier League and Region IV Far West Regional League). Automatic Regional League qualification was added to the National League format in January of this year, and two teams per age group from each of the four Regional Leagues will earn a spot in the 2013-2014 National League season.of the CFEL group that built the device. Scientists have successfully experimented with terahertz accelerators before, which could enable applications where large particle accelerators are just not feasible or necessary. "However, the technique is still in an early stage, and the performance of experimental terahertz accelerators has been limited by the relatively short section of interaction between the terahertz pulse and the electrons," says Kärtner.

For the new device, the team used a longer pulse comprising many cycles of terahertz waves. This multicycle pulse significantly extends the interaction section with the particles. "We feed the multicycle terahertz pulse into a waveguide that is lined with a dielectric material," says Zhang. Within the waveguide, the pulse's speed is reduced. A bunch of electrons is shot into the central part of