In this work, reservoir phenomenon in the decay phase of gradual solar energetic particle (SEP) events are investigated with two Helios and the IMP 8 spacecraft from 1976 January to 1980 March and two STEREO and the SOHO spacecraft from 2010 January to 2014 September. Using these data, 62 reservoir events of solar energetic protons were identified, and the effects of perpendicular diffusion and magnetic mirroring on the formation of the reservoir phenomenon have been studied. We find that the reservoir events could be observed in almost all longitudes in the ecliptic at 1 au; thus, the perpendicular diffusion in interplanetary space is an important mechanism to explain the uniform distribution of SEPs. Furthermore, in the 1976 April 30 event, the effects of magnetic mirroring associated with an interplanetary coronal mass ejection were observed during the reservoir phenomenon. Therefore, the effects of magnetic mirroring could also help to form the reservoir phenomenon. This study could improve the understanding of the propagation of SEPs in interplanetary space.

In this work, the quantitative relation of the intensity time profiles in the well-connected energetic particle events has been identified. Focusing on the propagation processes of energetic protons in the energy channels of about 13–64 MeV, solar energetic particle (SEP) events observed by STEREO A, STEREO B, and SOHO have been studied. The intensities observed by the spacecraft with the best magnetic connection to the source region tend to rise the fastest and have the highest peak intensities. In the cases without multiple injections or significant acceleration of particles by interplanetary shocks, particle intensities with the highest peaks are fitted by using a solution of the diffusion equation, and the time profiles of particle intensities could be described by two parameters. By fitting 59 energetic proton events, we find that the two parameters satisfy a power-law model in different events, and the distribution of peak time is also obtained. The power-law model helps one to obtain a quantitative relation of SEP intensities with the fitting function, and the distribution of peak time could provide a basis for determining the magnetic connection between the spacecraft and the source region.

In the decay phase of solar energetic particle (SEP) events, particle intensities observed by widely separated spacecraft usually present comparable intensities (within a factor of 2–3) that evolve similarly in time. The phenomenon of SEP events is called a reservoir, which could be observed frequently in intensive gradual SEP events. In this work, we find the effects of the magnetic boundary could help to form the reservoir phenomenon in energetic proton and electron events. In the 1978 January 1 and the 2000 November 8 SEP events, we find the effects of the magnetic boundary associated with the reservoir phenomenon were observed simultaneously in the sheath of magnetic cloud/interplanetary coronal mass ejection. Based on the observations, we suggest that the effects of the magnetic boundary could be due to the magnetic mirrors and/or the small diffusion coefficients in the sheath region and they could help to form the reservoir phenomenon in both the energetic proton and electron events in some large SEP events.

Objectives This study aims to compare the clinical effectiveness of transforaminal endoscopic spine system (TESSYS) technique combined with selective nerve root block (SNRB) in treating patients with far lateral lumbar disc herniation (FLDH) and patients with central or paracentral herniation (C/PDH). Patients and methods Between June 2015 and June 2019, a total of 204 patients (80 males, 124 females; mean age: 62.3±5.4 years; range, 51 to 66 years) with a herniated disc were included. Of these, 22 consecutive adult patients with FLDH formed the FLDH group, while 182 patients with C/PDH formed the C/PDH group. Considering that FLDH was a rare type of LDH and occurred outside the spinal canal, the patients with LDH in the spinal canal (C/PDH) were selected as the controls in our study. All cases received ultrasound-guided SNRB to identify the diseased disc and treated by the TESSYS technique. Data including demographics, duration of operation, duration of hospital stay, surgical cost, complications, Visual Analog Scale (VAS) scores for the back and leg, and Oswestry Disability Index (ODI) scores and the modified MacNab criteria were analyzed. Results The FLDH group presented the similar clinical outcomes and costs with the C/PDH group. No significant differences in the VAS score, ODI score, and Macnab score were observed between the groups (p>0.05 for all). Both groups showed the significantly improved postoperative VAS scores on Day 3, at 1, 3, 6, and 12 months compared to baseline. The postoperative ODI scores at 6 and 12 months were also significantly improved (p<0.05). At the final follow-up at 12 months, the FLDH group showed the MacNab criteria rating excellent and good of 81.8% and C/PDH group showed 84.62%. Conclusion The FLDH patients presented the comparable clinical effectiveness with C/PDH patients. Based on these findings, the TESSYS technique combined with ultrasound-guided SNRB for FLDH is safe and feasible with caution, although the risk of nerve root injury may be worried.