arXiv subjects

Julie Rolla

Publications and source records attributed to Julie Rolla.

6 recordsLinked to original sources

arXiv2026

Lunar Reflective Interferometry

We present the method of lunar reflection interferometry (LRI) in which a virtual interferometer can be formed by using a spacecraft-borne antenna in lunar orbit that receives both direct rays and those reflected from the lunar surface. The technique exploits the method of images and is akin to the classic "sea cliff" interferometer, with the Moon's surface, primarily the lunar Maria, replacing the ocean surface. We describe the method in detail, demonstrate that significant portions of the Moon's surface are sufficiently smooth at low radio frequencies, $\nu \lesssim 10\,\mathrm{MHz}$, for the technique to work, and outline a spacecraft instrument implementation. We describe potential systematic errors and how they could be mitigated. We present several astrophysics applications of the method.

astro-ph.IM↗

arXiv2026

ECLIPSE: An Evolutionary Computation Library for Instrumentation Prototyping in Scientific Engineering

Designing scientific instrumentation often requires exploring large, highly constrained design spaces using computationally expensive physics simulations. These simulators pose substantial challenges for integrating evolutionary computation (EC) into scientific design workflows. EC typically requires numerous design evaluations, making the integration of slow, low-throughput simulators challenging, as they are optimized for accuracy and ease of use rather than throughput. We present ECLIPSE, an evolutionary computation framework built to interface directly with complex, domain-specific simulation tools while supporting flexible geometric and parametric representations of scientific hardware. ECLIPSE provides a modular architecture consisting of (1) Individuals, which encode hardware designs using domain-aware, physically constrained representations; (2) Evaluators, which prepare simulation inputs, invoke external simulators, and translate the simulator's outputs into fitness measures; and (3) Evolvers, which implement EC algorithms suitable for this domain. We evolve solutions for two novel space-science applications: 3D antennas optimized for directional sensitivity and spacecraft geometries optimized for drag reduction. Notably, we identify antennas with directional sensitivity roughly comparable to the expected sensitivity of two-antenna interferometric arrays, representing potential cost-savings. ECLIPSE enables interdisciplinary teams of physicists, engineers, and EC researchers to collaboratively explore designs for scientific hardware while leveraging existing domain-specific simulation software.

cs.NE↗

arXiv2025

Compression and Reconnection Investigations of the MagnetoPause (CRIMP): A Mission Concept to Uncover the Impact of Mesoscale Reconnection and Plasma Outflow Processes at the Dayside Magnetopause

The Compression and Reconnection Investigations of the Magnetopause (CRIMP) mission is a hypothesis-driven, Heliophysics Medium-Class Explorer (MIDEX) Announcement of Opportunity (AO) mission concept designed to study mesoscale structures and particle outflow along Earth's magnetopause using two identical spacecraft. CRIMP is designed to uncover the impact of magnetosheath mesoscale drivers, dayside magnetopause mesoscale phenomenological processes and structures, and localized plasma outflows on magnetic reconnection and the energy transfer process in the dayside magnetosphere. CRIMP accomplishes this through uniquely phased spacecraft configurations that allow multipoint, contemporaneous measurements at the magnetopause. This enables an unparalleled look at mesoscale spatial differences along the dayside magnetopause on the scale of 1-3 Earth Radii (Re). Through these measurements, CRIMP will uncover how local mass density enhancements affect global reconnection, how mesoscale structures drive magnetopause dynamics, and if the magnetopause acts as a perfectly absorbing boundary for radiation belt electrons. This allows CRIMP to determine the spatial scale size, extent, and temporal evolution of energy and mass transfer processes at the magnetopause - crucial measurements to determine how the solar wind energy input to the magnetosphere is transmitted between regions and across scales.

physics.space-ph↗

arXiv2024

An Instrument Error Budget for Space-Based Absolute Flux Measurements of the Sky Synchrotron Spectrum Below 20 MHz

This work describes the instrumental error budget for space-based measurements of the absolute flux of the sky synchrotron spectrum at frequencies below the ionospheric cutoff (<20 MHz). We focus on an architecture using electrically short dipoles onboard a small satellite. The error budget combines the contributions of the dipole dimensions, plasma noise, stray capacitance, and front-end amplifier input impedance. We treat the errors using both a Monte Carlo error propagation model and an analytical method. This error budget can be applied to a variety of experiments and used to ultimately improve the sensing capabilities of space-based electrically short dipole instruments. The impact of individual uncertainty components, particularly stray capacitance, is explored in more detail.

astro-ph.IM↗

arXiv2021

Evolving Antennas for Ultra-High Energy Neutrino Detection

Evolutionary algorithms are a type of artificial intelligence that utilize principles of evolution to efficiently determine solutions to defined problems. These algorithms are particularly powerful at finding solutions that are too complex to solve with traditional techniques and at improving solutions found with simplified methods. The GENETIS collaboration is developing genetic algorithms to design antennas that are more sensitive to ultra high energy neutrino induced radio pulses than current detectors. Improving antenna sensitivity is critical because UHE neutrinos are rare and require massive detector volumes with stations dispersed over hundreds of km squared. The GENETIS algorithm evolves antenna designs using simulated neutrino sensitivity as a measure of fitness by integrating with XFdtd, a finite difference time domain modeling program, and with simulations of neutrino experiments. The best antennas will then be deployed in ice for initial testing. The genetic algorithm's aim is to create antennas that improve on the designs used in the existing ARA experiment by more than a factor of 2 in neutrino sensitivities. This research could improve antenna sensitivities in future experiments and thus accelerate the discovery of UHE neutrinos. This is the first time that antennas have been designed using genetic algorithms with a fitness score based on a physics outcome, which will motivate the continued use of genetic algorithm designed instrumentation in astrophysics and beyond. This proceeding will report on advancements to the algorithm, steps taken to improve the genetic algorithm performance, the latest results from our evolutions, and the manufacturing road map.

astro-ph.IM↗

arXiv2020

Evolving Antennas for Ultra-High Energy Neutrino Detection

Evolutionary algorithms borrow from biology the concepts of mutation and selection in order to evolve optimized solutions to known problems. The GENETIS collaboration is developing genetic algorithms for designing antennas that are more sensitive to ultra-high energy neutrino induced radio pulses than current designs. There are three aspects of this investigation. The first is to evolve simple wire antennas to test the concept and different algorithms. Second, optimized antenna response patterns are evolved for a given array geometry. Finally, antennas themselves are evolved using neutrino sensitivity as a measure of fitness. This is achieved by integrating the XFdtd finite-difference time-domain modeling program with simulations of neutrino experiments.

astro-ph.IM↗