In this letter the structure of the ion diffusion region of magnetic reconnection at Earths magnetopause is investigated using the Magnetospheric Multiscale (MMS) spacecraft. The ion diffusion region ...is characterized by a strong DC electric field, approximately equal to the Hall electric field, intense currents, and electron heating parallel to the background magnetic field. Current structures well below ion spatial scales are resolved, and the electron motion associated with lower hybrid drift waves is shown to contribute significantly to the total current density. The electron heating is shown to be consistent with large-scale parallel electric fields trapping and accelerating electrons, rather than wave-particle interactions. These results show that sub-ion scale processes occur in the ion diffusion region and are important for understanding electron heating and acceleration.
During a magnetopause crossing the Magnetospheric Multiscale spacecraft encountered an electron diffusion region (EDR) of asymmetric reconnection. The EDR is characterized by agyrotropic beam and ...crescent electron distributions perpendicular to the magnetic field. Intense upper-hybrid (UH) waves are found at the boundary between the EDR and magnetosheath inflow region. The UH waves are generated by the agyrotropic electron beams. The UH waves are sufficiently large to contribute to electron diffusion and scattering, and are a potential source of radio emission near the EDR. These results provide observational evidence of wave-particle interactions at an EDR, and suggest that waves play an important role in determining the electron dynamics.
The nature of the mechanism responsible for producing the spectacular, geometrically thin, spherical shells found around some carbon stars has been an enigma for some time. Based on extensive ...radiative transfer modelling of both CO line emission and dust continuum radiation for all objects with known detached molecular shells, we present compelling evidence that these shells show clear signs of interaction with a surrounding medium. The derived masses of the shells increase with radial distance from the central star while their velocities decrease. A simple model for interacting winds indicate that the mass-loss rate producing the faster moving wind has to be almost two orders of magnitudes higher (~10^-5 solar masses per year) than the slower AGB wind (a few 10^-7 solar masses per year) preceding this violent event. At the same time, the present-day mass-loss rates are very low indicating that the epoch of high mass-loss rate was relatively short, on the order of a few hundred years. This, together with the number of sources exhibiting this phenomenon, suggests a connection with He-shell flashes (thermal pulses). We report the detection of a detached molecular shell around the carbon star DR Ser, as revealed from new single-dish CO (sub-)millimetre line observations. The properties of the shell are similar to those characterising the young shell around U Cam.
Patients in the forensic mental health services (FMHS) with a mental disorder, a co-occurring substance use disorder (SUD), and high risk of aggressive antisocial behavior (AAB) are sometimes ...referred to as the ‘triply troubled’. They suffer poor treatment outcomes, high rates of criminal recidivism, and increased risk of drug related mortality. To improve treatment for this heterogeneous patient group, more insight is needed concerning their co-occurring mental disorders, types of substances used, and the consequent risk of AAB.
A three-step latent class analysis (LCA) was used to identify clinically relevant subgroups in a sample of patients (n = 98) from a high-security FMHS clinic in Sweden based on patterns in their history of mental disorders, SUD, types of substances used, and AAB.
A four-class model best fit our data: class 1 (42%) had a high probability of SUD, psychosis, and having used all substances; class 2 (26%) had a high probability of psychosis and cannabis use; class 3 (22%) had a high probability of autism and no substance use; and class 4 (10%) had a high probability of personality disorders and having used all substances. Both polysubstance classes (1 and 4) had a significantly more extensive history of AAB compared to classes 2 and 3. Class 3 and class 4 had extensive histories of self-directed aggression.
The present study helps disentangle the heterogeneity of the ‘triply troubled’ patient group in FMHS. The results provide an illustration of a more person-oriented perspective on patient comorbidity and types of substances used which could benefit clinical assessment, treatment planning, and risk-management among patients in forensic psychiatric care.
•Latent class analysis with patients' mental disorders and history of substance use.•Polysubstance classes had extensive history of AAB and earlier debut in criminality.•Cannabis-limited class had fewest incidents of AAB and latest debut in criminality.•Autism class had low probability of substance use but numerous self-harm incidents.•Person oriented analysis provides a clinically useful perspective on comorbidities.
We report observations from the Magnetospheric Multiscale satellites of large-amplitude, parallel, electrostatic waves associated with magnetic reconnection at the Earth's magnetopause. The observed ...waves have parallel electric fields (E(sub parallel)) with amplitudes on the order of 100 mV/m and display nonlinear characteristics that suggest a possible net E(sub parallel). These waves are observed within the ion diffusion region and adjacent to (within several electron skin depths) the electron diffusion region. They are in or near the magnetosphere side current layer. Simulation results support that the strong electrostatic linear and nonlinear wave activities appear to be driven by a two stream instability, which is a consequence of mixing cold (less than 10eV) plasma in the magnetosphere with warm (approximately 100eV) plasma from the magnetosheath on a freshly reconnected magnetic field line. The frequent observation of these waves suggests that cold plasma is often present near the magnetopause.
Using MMS high‐resolution measurements, we present the first observation of fast electron jet (Ve ~2,000 km/s) at a dipolarization front (DF) in the magnetotail plasma sheet. This jet, with scale ...comparable to the DF thickness (~ 0.9 di), is primarily in the tangential plane to the DF current sheet and mainly undergoes the E × B drift motion; it contributes significantly to the current system at the DF, including a localized ring‐current that can modify the DF topology. Associated with this fast jet, we observed a persistent normal electric field, strong lower hybrid drift waves, and strong energy conversion at the DF. Such strong energy conversion is primarily attributed to the electron‐jet‐driven current (E ⋅ je ≈ 2 E ⋅ ji), rather than the ion current suggested in previous studies.
Key Points
For the first time, fast electron jet is observed at dipolarization front
This jet is responsible for current and energy conversion at dipolarization front
Quantitatively, the partition of energy conversion is E ⋅ je ≈ 2 E ⋅ ji
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