Huntsville, Alabama, Marx Meter Array 2: Upgrade and Capability

This paper introduces the newly developed 2^nd generation Huntsville Alabama Marx Meter Array (HAMMA 2), comprised of 10 electric field change meters with a typical baseline of 10 -20 km. Compared to the previous HAMMA sensor, the HAMMA 2 has a more portable design with antenna, electronics, FPGA, GPS, and computer integrated into one standalone sensor powered by solar energy. The HAMMA 2 is equipped with two channels with different sensitivities. The time decay constants for the slow and fast channels are 100 ms and 100 µs, respectively. The sampling rate is 1 MS/s for the slow channel and 10 MS/s for the fast channel. These channels allow HAMMA 2 to measure the electric field changes over the bandwidth from ~1Hz to ~2.5MHz. While the fast channel can be used for lightning mapping, the slow channel allows for measurement of the energetics of each discharge, including charge neutralized. The timing accuracy of the fast channel was experimentally determined to be ~100 to 300 ns, which could lead to great improvement in location accuracy. The HAMMA 2 is capable of using both typical time of arrival (TOA) and cross-correlation techniques to map lightning. Analysis of preliminary data collected by the HAMMA2 will be presented.