Extracting astrophysical information of highly eccentric binaries in the millihertz gravitational wave band

Physical Review D - Particles, Fields, Gravitation, and Cosmology American Physical Society 111:4 (2025) 043018

Authors:

Zeyuan Xuan, Smadar Naoz, Alvin KY Li, Bence Kocsis, Erik Petigura, Alan M Knee, Jess McIver, Kyle Kremer, Will M Farr

Abstract:

Wide, highly eccentric (𝑒 >0.9) compact binaries can naturally arise as progenitors of gravitational wave (GW) mergers. These systems are expected to have a significant population in the mHz band (e.g., ∌3–45 detectable stellar-mass binary black holes with 𝑒 >0.9 in the Milky Way), with their GW signals characterized by “repeated bursts” emitted upon each pericenter passage. In this study, we show that the detection of mHz GW signals from highly eccentric stellar mass binaries in the local universe can strongly constrain their orbital parameters. Specifically, it can achieve a relative measurement error of ∌10−6 for orbital frequency and ∌1% for eccentricity (as 1 −𝑒) in most of the detectable cases. On the other hand, the binary’s mass ratio, distance, and intrinsic orbital orientation may be less precisely determined due to degeneracies in the GW waveform. We also perform mock LISA data analysis to evaluate the realistic detectability of highly eccentric compact binaries. Our results show that highly eccentric systems could be efficiently identified when multiple GW sources and stationary Gaussian instrumental noise are present in the detector output. This work highlights the potential of extracting the signal of “bursting” LISA sources to provide valuable insights into their orbital evolution, surrounding environment, and formation channels.

Collisionless conduction in a high-beta plasma: a collision operator for whistler turbulence

Journal of Plasma Physics Cambridge University Press (CUP) 91:1 (2025) e20

Authors:

Evan L Yerger, Matthew W Kunz, Archie FA Bott, Anatoly Spitkovsky

The Radio & Plasma Wave Investigation (RPWI) for the JUpiter ICy moons Explorer (JUICE)

Space Science Reviews Springer Science and Business Media LLC 221:1 (2025) 1

Authors:

J-E Wahlund, JES Bergman, L ÅhlĂ©n, W Puccio, B Cecconi, Y Kasaba, I MĂŒller-Wodarg, H Rothkaehl, M Morawski, O Santolik, J Soucek, J Grygorczuk, Ɓ Wisniewski, P Henri, JL Rauch, O Le Duff, A RetinĂČ, M Mansour, S Stverak, J Laifr, D Andrews, M AndrĂ©, I Benko, M Berglund, V Cripps, C Cully, J Davidsson, A Dimmock, NJT Edberg, AI Eriksson, J Fredriksson, R Gill, S Gomis, B Holback, S-E Jansson, F Johansson, EPG Johansson, Y Khotyaintsev, B MĂ„rtensson, MW Morooka, T Nilsson, D Ohlsson, D Pelikan, L Richard, F Shiwa, E Vigren, HC Wong, X Bonnin, JN Girard, L Grosset, F Henry, L Lamy, J-P Lebreton, P Zarka, Y Katoh, H Kita, A Kumamoto, H Misawa, F Tsuchiya, M Galand, T Barcinski, J Baran, T Kowalski, P Szewczyk, B Grison, J Jansky, I Kolmasova, R Lan, D Pisa, U Taubenschuss, L Uhlir, K Bochra, M Borys, M Duda, T Kucinski, M Ossowski, P Palma, M Tokarz, F Colin, P Dazzi, E De LĂ©on, T Hachemi, A-L Millet, O Randrianboarisson, O Sene, T Chust, O Le Contel, P Canu, L Hadid, F Sahraoui, Y Zouganelis, D Alison, N Ba, A Jeandet, M Lebassard, J-D Techer, F Mehrez, L Varizat, AV Sumant, G Sou, P Hellinger, P Travnicek, L Bylander, G Giono, N Ivchenko, A Kullen, L Roth, A Vaivads, K Tanimoto, H Mizuno, A Sawamura, T Suzuki, M Namiki, S Fujishima, K Asai, T Shimoyama, M Fujii, Y Sato, J Birch, B Bakhit, G Greczynski, P Gare, S Landström, R LeLetty, E Ryszawa, I Torralba, JL Trescastro, S Osipenco, U Wiklund, A Roos, JC Söderström, O Björneholm, G Fischer, T Nyberg, KK Kovi, M Balikhin, KH Yearby, M Holmberg, CM Jackman, CK Louis, A Rhouni, V Leray, N Geyskens, C Berthod, B Lemaire, A ClĂ©mencon, G Wattieaux, N AndrĂ©, P Garnier, V GĂ©not, P Louarn, A Marchaudon, R Modolo, C-A Baskevitch, LG Hess, L Leclercq, J Saur, T Kimura, H Kojima, S Yagitani, Y Miyoshi

Abstract:

Abstract The Radio & Plasma Wave Investigation (RPWI) onboard the ESA JUpiter ICy moons Explorer (JUICE) is described in detail. The RPWI provides an elaborate set of state-of-the-art electromagnetic fields and cold plasma instrumentation, including active sounding with the mutual impedance and Langmuir probe sweep techniques, where several different types of sensors will sample the thermal plasma properties, including electron and ion densities, electron temperature, plasma drift speed, the near DC electric fields, and electric and magnetic signals from various types of phenomena, e.g., radio and plasma waves, electrostatic acceleration structures, induction fields etc. A full wave vector, waveform, polarization, and Poynting flux determination will be achieved. RPWI will enable characterization of the Jovian radio emissions (including goniopolarimetry) up to 45 MHz, has the capability to carry out passive radio sounding of the ionospheric densities of icy moons and employ passive sub-surface radar measurements of the icy crust of these moons. RPWI can also detect micrometeorite impacts, estimate dust charging, monitor the spacecraft potential as well as the integrated EUV flux. The sensors consist of four 10 cm diameter Langmuir probes each mounted on the tip of 3 m long booms, a triaxial search coil magnetometer and a triaxial radio antenna system both mounted on the 10.6 m long MAG boom, each with radiation resistant pre-amplifiers near the sensors. There are three receiver boards, two Digital Processing Units (DPU) and two Low Voltage Power Supply (LVPS) boards in a box within a radiation vault at the centre of the JUICE spacecraft. Together, the integrated RPWI system can carry out an ambitious planetary science investigation in and around the Galilean icy moons and the Jovian space environment. Some of the most important science objectives and instrument capabilities are described here. RPWI focuses, apart from cold plasma studies, on the understanding of how, through electrodynamic and electromagnetic coupling, the momentum and energy transfer occur with the icy Galilean moons, their surfaces and salty conductive sub-surface oceans. The RPWI instrument is planned to be operational during most of the JUICE mission, during the cruise phase, in the Jovian magnetosphere, during the icy moon flybys, and in particular Ganymede orbit, and may deliver data from the near surface during the final crash orbit.

The Role of Kinetic Instabilities and Waves in Collisionless Magnetic Reconnection

Space Science Reviews Springer Science and Business Media LLC 221:1 (2025) 20

Authors:

DB Graham, G Cozzani, Yu V Khotyaintsev, VD Wilder, JC Holmes, TKM Nakamura, J BĂŒchner, K Dokgo, L Richard, K Steinvall, C Norgren, L-J Chen, H Ji, JF Drake, JE Stawarz, S Eriksson

Abstract:

Abstract Magnetic reconnection converts magnetic field energy into particle energy by breaking and reconnecting magnetic field lines. Magnetic reconnection is a kinetic process that generates a wide variety of kinetic waves via wave-particle interactions. Kinetic waves have been proposed to play an important role in magnetic reconnection in collisionless plasmas by, for example, contributing to anomalous resistivity and diffusion, particle heating, and transfer of energy between different particle populations. These waves range from below the ion cyclotron frequency to above the electron plasma frequency and from ion kinetic scales down to electron Debye length scales. This review aims to describe the progress made in understanding the relationship between magnetic reconnection and kinetic waves. We focus on the waves in different parts of the reconnection region, namely, the diffusion region, separatrices, outflow regions, and jet fronts. Particular emphasis is placed on the recent observations from the Magnetospheric Multiscale (MMS) spacecraft and numerical simulations, which have substantially increased the understanding of the interplay between kinetic waves and reconnection. Some of the ongoing questions related to waves and reconnection are discussed.

Insights into stripping losses of negative ions in an ITER-like pre-acceleration system

Plasma Physics and Controlled Fusion IOP Publishing 67:1 (2025) 015011

Authors:

A Navarro, M Barnes, N den Harder, D WĂŒnderlich, U Fantz