Sunspot groups and bipolar magnetic regions (BMRs) serve as an observational diagnostic of the solar cycle. We use Debrecen Photohelographic Data (DPD) from 1974-2014 that determined sunspot tilt angles from daily white light observations, and data provided by Li & Ulrich (2012) that determined sunspot magnetic tilt angle using Mount Wilson magnetograms from 1974-2012. The magnetograms allowed for BMR tilt angles that were anti-Hale in configuration, so tilt values ranged from 0 to 360 • rather than the more common ±90 • . We explore the visual representation of magnetic tilt angles on a traditional butterfly diagram by plotting the mean area-weighted latitude of umbral activity in each bipolar sunspot group, including tilt information. The large scatter of tilt angles over the course of a single cycle and hemisphere prevents Joy's law from being visually identified in the tilt-butterfly diagram without further binning. The average latitude of anti-Hale regions does not differ from the average latitude of all regions in both hemispheres. The distribution of anti-Hale sunspot tilt angles are broadly distributed between 0 and 360°with a weak preference

The axes of solar active regions are inclined relative to the east-west direction, with the tilt angle tending to increase with latitude ("Joy's law"). Observational determinations of Joy's law have been based either on white-light images of sunspot groups or on magnetograms, where the latter have the advantage of measuring directly the physically relevant quantity (the photospheric field), but the disadvantage of having been recorded routinely only since the mid-1960s. White-light studies employing the historical Mount Wilson (MW) database have yielded tilt angles that are smaller and that increase less steeply with latitude than those obtained from magnetic data. We confirm this effect by comparing sunspot-group tilt angles from the Debrecen Photoheliographic Database with measurements made by Li and Ulrich using MW magnetograms taken during cycles 21-23. Whether white-light or magnetic data are employed, the median tilt angles significantly exceed the mean values, and provide a better characterization of the observed distributions. The discrepancy between the white-light and magnetic results is found to have two main sources. First, a substantial

We report Magnetospheric Multiscale (MMS) observations of a reconnecting current sheet in the presence of a weak density asymmetry with large guide field at the dayside magnetopause. An ion diffusion region (IDR) was detected associated with this current sheet. Parallel current dominated over the perpendicular current in the IDR, as found in previous studies of component reconnection. Electrons were preferentially heated parallel to the magnetic field within the IDR. The heating was manifested as a flattop distribution below 400 eV. Two types of electromagnetic electron whistler waves were observed within the regions where electrons were heated. One type of whistler wave was associated with nonlinear structures in E|| with amplitudes up to 20 mV/m. The other type was not associated with any structures in E||. Poynting fluxes of these two types of whistler waves were directed away from the X‐line. We suggest that the nonlinear evolution of the oblique whistler waves gave rise to the solitary structures in E||. There was a perpendicular super‐Alfvénic outflow jet that was carried by magnetized electrons. Intense electrostatic lower hybrid drift waves were localized in the current sheet center and were probably driven by the super‐Alfvénic electron jet, the velocity of which was approximately equal to the diamagnetic drift of demagnetized ions. Our observations suggest that the guide field significantly modified the structures (Hall electromagnetic fields and current system) and wave properties in the IDR.

Prior to the 2018 landing of the InSight mission, the InSight science team proposed locating Marsquakes using multiple orbit surface waves, independent of seismic velocity models, for events larger than MW4.6. The S1222a MW4.7 of 4 May 2022 is the largest Marsquake recorded and the first large enough for this method. Group arrivals of the first three orbits of Rayleigh waves are determined to derive the group velocity, epicentral distance, and origin time. The mean distance of 36.9 ± 0.3° agrees with the Marsquake Service (MQS) distance based on body wave measurements of 37.0 ± 1.6°. The origin time from surface waves is systematically later than the MQS origin time by 20 s. Backazimuth estimation is similar to body wave estimations from MQS although suggesting a shift to the south. Backazimuth estimates from R2 and R3 are more scattered, but do show clear elliptical motion.

Rapid injection of MeV electrons associated with strong substorm dipolarization has been suggested as a potential explanation for some radiation belt enhancement events. However, it has been difficult to quantify the contribution of MeV electron injections to radiation belt enhancements. This paper presents two isolated MeV electron injection events for which we quite precisely quantify how the entire outer‐belt immediately changed with the injections. Tracking detailed outer‐belt evolution observed by Van Allen Probes, for both events, we identify large step‐like relativistic electron enhancements (roughly 1 order of magnitude increase for ∼2 MeV electron fluxes) for L ≳ 3.8 and L ≳ 4.6, respectively, that occurred on ∼30‐min time scales nearly instantaneously with the injections. The enhancements occurred almost simultaneously for 10s keV to multi‐MeV electrons, with the lowest L of enhancement region located farther out for higher energy. The outer‐belt stayed at these new levels for ≳several hours without substantial subsequent enhancements.